Process for polymerizing a methacrylic ester or an acrylic ester

ABSTRACT

(1) A methacrylic ester or an acrylic ester is anionically polymerized, using a polymerization initiator compound comprising an addition reaction product of a conjugated diene compound and an organic alkali metal compound, in the presence of a tertiary organoaluminum compound having in the molecule thereof a chemical structure represented by a formula: Al—O—Ar wherein Ar represents an aromatic ring; or  
     (2) a methacrylic ester or an acrylic ester is anionically polymerized, using a polymerization initiator compound comprising an addition reaction product of an organic alkali metal compound and a compound having a 1,1-diaryl-1-alkene structure, by adding the ester in the form of a mixture with the above-mentioned specific tertiary organoaluminum compound to the polymerization system.  
     In this way, various species of the esters can be anionically polymerized with a high initiation efficiency and a high living polymerization property in a solvent which can easily be recovered and reused under a mild cooling condition, using an organic alkali metal compound which has relatively good convenience.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a polymerization process givingsuperior reaction results such as initiation efficiency, comprising ananionic polymerization of a methacrylic ester or an acrylic ester in thepresence of a specific organoaluminum compound, using a specificpolymerization initiator compound. The present invention also relates toa process for producing a polymer such as a block copolymer, wherein theabove-mentioned polymerization process is used.

[0003] 2. Related Art of the Invention

[0004] Not only realization of high living polymerization property butalso an improvement in initiation efficiency are important for anionicpolymerization. The improvement in the initiation efficiency isespecially important for synthesis of a block copolymer as well asenhancement of use efficiency of a polymerization initiator compound.For example, the following process is assumed: a process forsynthesizing a block copolymer comprising a polymer block resulting froma certain kind of monomer (hereinafter referred to as a first monomer)and another polymer block resulting from another kind of monomer(hereinafter referred to as a second monomer), comprising polymerizingthe first monomer to synthesize a living polymer, and then polymerizingthe second monomer by use of the living monomer as a polymerizationinitiator compound. If the initiation efficiency of the living polymer(block efficiency in this case) is low, a product which is actuallyobtained is a mixture of the block copolymer and a polymer resultingfrom the first monomer. In many cases, the above-mentioned impurityproduced by interruption of the polymerization causes a remarkable dropin performances of the block copolymer. It is known that, for example, atriblock copolymer having a structure of a hard block/a soft block/ahard block has properties as a thermoplastic elastomer. If a polymerhaving only a hard block or a diblock copolymer having a structure of ahard block/a soft block is mixed with this type triblock copolymer,mechanical properties such as tensile strength drop. Block copolymersare frequently used as compatibilizer for different resins. However, ifa homopolymer is mixed with a used block copolymer, the function as thecompatibilizer deteriorates so that good points which respective resinsoriginally have in a resultant resin composition are not sufficientlyexhibited.

[0005] As a process for heightening initiation efficiency in anionicpolymerization of a methacrylic ester or an acrylic ester, there isknown a process comprising the steps of subjecting an organic alkalimetal compound, for example, an alkyl lithium such as butyllithium, or alithiated polymer such as polystyryllithium to addition reaction with1,1-diphenylethylene or α-methylstyrene to prepare a compound having, atits terminal site, a diphenylmethylene anion structure or aphenylmethylene anion structure; and then polymerizing a methacrylicester anionically in a solvent comprising tetrahydrofuran alone or amixture of tetrahydrofuran and toluene at a low temperature, forexample, −60° C. or lower, using the above-mentioned compound as apolymerization initiator compound (Macromolecules, Vol. 23, pp.2618-2622 (1990)). A polar solvent, such as tetrahydrofuran used in thisprocess, is easily mixed in waste water at the time of washing withwater after the polymerization, and further is not easily separated fromthe waste water. Therefore, the polar solvent is not suitable forindustrial use. As a result, in order to carry out industrially anionicpolymerization in a solution of a methacrylic ester or an acrylic ester,it is desired to use a nonpolar solvent, such as a hydrocarbon basedsolvent, as a solvent.

[0006] As a process for making it possible to polymerize a methacrylicester or an acrylic ester anionically in a hydrocarbon based solvent, aprocess wherein an organoaluminum compound causes to be present in thepolymerization system is suggested. It is considered that in this case,the organoaluminum compound has a function of lowering nucleophilicityof the growing terminal of the polymer and stabilizing the growingterminal by coordination, as a Lewis acid, to a used polymerizationinitiator compound or the growing terminal of the living polymer in themiddle of the polymerization. Examples of reports on such apolymerization process are as follows.

[0007] (1) Anionic polymerization of a methacrylic ester usingtert-butyllithium was conducted in the presence of an organoaluminumcompound such as a trialkylaluminum or a dialkyl(diphenylamino)aluminumin toluene at −78° C. to obtain a methacrylic ester polymer having anarrow molecular weight distribution (JP-B-H7-57766).

[0008] (2) Anionic polymerization of a methacrylic ester using anorganolithium compound such as tert-butyllithium was conducted in thepresence of a specific organoaluminum compound having one or more bulkygroups (for example, triisobutylaluminum ordiisobutyl(2,6-di-tert-butyl-4-methylphenoxy) aluminum) in a hydrocarbonsolvent at a temperature of about −10° C., which is a relatively mildcooling condition (U.S. Pat. No. 5,180,799).

[0009] (3) Anionic polymerization of a methacrylic ester or an acrylicester using tert-butyllithium was conducted in the presence ofmethylbis(2,6-di-tert-butylphenoxy)aluminum orethylbis(2,6-di-tert-butylphenoxy)aluminum in toluene at a temperatureof −60° C. or −70° C. to obtain a homopolymer or a block copolymerhaving a narrow molecular weight distribution (Polymer Preprints, Japan,Vol. 46, No. 7, pp. 1081-1082 (1997) and Vol. 47, No. 2, p.179 (1998)).

[0010] (4) An organolithium compound such as tert-butyllithium,sec-butyllithium, ethyl α-lithioisobutyrate, 1,1-diphenylhexyllithiumwas mixed with an organoaluminum compound such asmethylbis(2,6-di-tert-butylphenoxy)aluminum,ethylbis(2,6-di-tert-butylphenoxy)aluminum ortris(2,6-di-tert-butylphenoxy)aluminum, and then the mixture was broughtinto contact with methyl methacrylate to anionically polymerize methylmethacrylate in a nonpolar organic solvent such as toluene at about roomtemperature. In this way, an initiation efficiency of 0.05-0.63 wasattained (U.S. Pat. No. 5,656,704).

[0011] (5) Anionic polymerization of a methacrylic ester or an acrylicester using an organolithium compound such as methyl α-lithioisobutyrateor tert-butyllithium was conducted in the presence of an organoaluminumcompound, such as a trialkylaluminum, and an ester compound, an ethercompound or an organic quaternary salt in a hydrocarbon based solventsuch as toluene at a temperature of about −80° C. to 0° C., so as toobtain a polymer having a narrow molecular weight distribution(Macromolecules, Vol. 31, pp. 573-577 (1998) and InternationalPublication WO98/23651).

[0012] (6) An organolithium compound such as n-butyllithium wassubjected to addition-reaction with butadiene to preparepolybutadienyllithium, and then the polybutadienyllithium was reactedwith tert-butyl methacrylate in the presence of a trialkylaluminum suchas triethylaluminum at 50° C., so as to obtain a block copolymer (U.S.Pat. No. 5,514,753).

[0013] According to the above-mentioned processes (1)-(6), anionicpolymerization of a methacrylic ester or an acrylic ester can beattained in a hydrocarbon based solvent. However, in order to use theseprocesses as industrial polymerization processes, they have thefollowing points to be further improved.

[0014] The polymerization initiator compound used to polymerize amethacrylic ester or an acrylic ester in specific polymerizationexamples in the above-mentioned (1)-(3) processes is limited totert-butyllithium. It can be presumed that in order to attain goodpolymerization results in these polymerization examples, it is preferredto use tert-butyllithium. However, tert-butyllithium has intenseself-ignition ability. Thus, if tert-butyllithium is industrially used,problems about safety and handling performances thereof upontransportation and storage thereof arise.

[0015] In the processes (1) and (3), the polymerization temperaturesused in specific polymerization examples therein are very lowtemperatures, such as about −80 to −60° C. It can be presumed that inorder to attain good polymerization results in these polymerizationprocesses, it is preferred to use very low temperatures as describedabove. However, many utilities are necessary for cooling to suchtemperatures; therefore, the processes are industrially disadvantageous.

[0016] In the process (4), almost all of the initiation efficiencies inspecific polymerization examples of methyl methacrylate are 0.5 or lesseven in examples wherein tert-butyllithium, which can give relativelygood polymerization results, is used as a polymerization initiatorcompound. In an example wherein sec-butyllithium, which is apolymerization initiator compound that is relatively good in handlingperformance, is used, the initiation efficiency thereof is 0.17. Thus,the initiation efficiencies are on an insufficient level.

[0017] The polymerization initiator compounds used in specific examplesin the process (5) are limited to tert-butyllithium and ethylα-lithioisobutyrate. It can be presumed that in order to attain goodpolymerization results, it is preferred to use these polymerizationinitiator compounds. As described above, tert-butyllithium has problemsfor industrial use from the standpoint of safety and handlingperformance. Synthesis operation for producing ethyl α-lithioisobutyrateand subsequent purification operation are complicated. Therefore, it isdifficult to say that ethyl α-lithioisobutyrate is suitable forindustrial use.

[0018] The inventor et al. tried to reproduce the process (6)experimentally, but could not obtain desired results. That is, theinventor et al. prepared specified polybutadienyllithium on the basis ofthe specific production examples described as the process (6), and thenreacted the polybutadienyllithium with tert-butyl methacrylate in thepresence of triethylaluminum at 50° C., but the initiation efficiency ofthe polybutadienyllithium was low in the present polymerization system.A finally obtained product was a mixture of a block copolymer andpolybutadiene. Accordingly, the process (6) has problems when thisprocess is adopted for industrial production for which highreproducibility is required.

[0019] Furthermore, the inventor et al. made experimental investigationson the processes (1)-(6). As a result, it was proved that polymerizationof esters of a primary alcohol and methacrylic acid or acrylic acid,such as methyl methacrylate and n-butyl acrylate, does not advance inmany cases, or that even if polymerization reaction thereof advances,reaction results such as initiation efficiency and living polymerizationproperty drop as compared with polymerization of esters of a tertiaryalcohol and methacrylic acid, such as tert-butyl methacrylate.

[0020] 1,1-Diphenylethylene has no polymerizing ability, and additionreaction of 1,1-diphenylethylene of one molecule with a monovalentanionic compound of one molecule gives an addition reaction product.This addition reaction product has relatively low nucleophilicity and isa stable anionic compound. For this reason, 1,1-diphenylethylene isuseful as an anionic modifying agent for alkali metal compounds or aterminal modifying agent for living polymers. As an example of theprocess (4), there is described an example wherein methyl methacrylateis polymerized, using 1,1-diphenylhexyllithium, which corresponds to anaddition reaction product of 1, 1-diphenylethylene and n-butyllithium,as a polymerization initiator agent. However, the initiation efficiencythereof is a low value of 0.5 or less.

[0021] In order to make anionic polymerization of a methacrylic ester oran acrylic ester suitable for industrial accomplishment, the followingare important: living polymerization property is high; initiationefficiency (block efficiency in the case of a block copolymerization) ishigh; a hydrocarbon based solvent can be used as a solvent media for thepolymerization; the scope of polymerization initiator compounds orprecursors thereof (organic alkali metal compounds) that can be used iswide; and cooling conditions upon the polymerization can be made mild.Furthermore, a process making it possible to polymerize an ester of aprimary alcohol and methacrylic acid or acrylic acid while satisfyingthese requirements is desired as an industrial production process fromthe standpoint of highly wide use.

SUMMARY OF THE INVENTION

[0022] An object of the present invention is to provide a polymerizationprocess making it possible to attain high initiation efficiency (blockefficiency in the case of a block copolymerization) and high livingpolymerization property even when in anionic polymerization of amethacrylic ester or an acrylic ester, an ester of a primary alcohol andmethacrylic acid or acrylic acid, which is in general liable to givelowered polymerization results, is used, a compound which is relativelygood in safety and handling performance is used as a polymerizationinitiator compound or a precursor thereof, a hydrocarbon based solventwhich can easily be recovered and reused is used as a solvent media forpolymerization and a relatively high temperature condition (that is, arelatively mild cooling condition) is adopted as polymerizationtemperature. According to this polymerization process, it is possible toproduce a polymer having a narrow molecular weight distribution andproduce a block copolymer containing a small quantity of impurities suchas a homopolymer.

[0023] Another object of the present invention is to provide a processfor producing a polymer with industrial advantage, using thepolymerization process having the above-mentioned superior advantages.

[0024] The inventors et al. made eager investigations to attain theabove-mentioned objects. As a result, it has been found that byconducting anionic polymerization of a methacrylic ester or an acrylicester in the presence of a specific organoaluminum compound using aspecific polymerization initiator compound, it is possible to attain theabove-mentioned theme about the application scopes of the methacrylicester or acrylic ester, the polymerization initiator compound (or theprecursor thereof) and the solvent media for polymerization, theabove-mentioned theme about the polymerization condition (temperaturecondition) and the above-mentioned polymerization results (theinitiation efficiency and the living polymerization property). Theinventor et al. have found that by adding a methacrylic ester or anacrylic ester, as well as a specific organoaluminum compound, to ananionic polymerization system containing a specific polymerizationinitiator compound, it is also possible to attain the above-mentionedtheme about the application scopes of the methacrylic ester or acrylicester, the polymerization initiator compound (or the precursor thereof)and the solvent media for polymerization, the above-mentioned themeabout the polymerization condition (temperature condition) and theabove-mentioned polymerization results (the initiation efficiency andthe living polymerization property). On the basis of these findings, theinventors have made the present invention.

[0025] That is, a first aspect of the present invention is apolymerization process for polymerizing a methacrylic ester or anacrylic ester anionically, using a polymerization initiator compound,wherein an addition reaction product of a conjugated diene compound andan organic alkali metal compound is used as the polymerization initiatorcompound, and a tertiary organoaluminum compound having in the moleculethereof a chemical structure represented by a formula: Al—O—Ar whereinAr represents an aromatic ring is caused to be present in thepolymerization system (this polymerization process is referred to as a“polymerization process (X)” hereinafter).

[0026] A second aspect of the present invention is a process forproducing a polymer, comprising polymerizing a methacrylic ester or anacrylic ester by the polymerization process (X).

[0027] A third aspect of the present invention is a polymerizationprocess for polymerizing a methacrylic ester or an acrylic esteranionically, using a polymerization initiator compound, wherein anaddition reaction product of a compound having a 1,1-diaryl-1-alkenestructure and an organic alkali metal compound is used as thepolymerization initiator compound; and the methacrylic ester or theacrylic ester is mixed with a tertiary organoaluminum compound having inthe molecule thereof a chemical structure represented by a formula:Al—O—Ar wherein Ar represents an aromatic ring, and then the resultantmixture is added to the polymerization system (this polymerizationprocess is referred to as a “polymerization process (Y)” hereinafter).

[0028] A fourth aspect of the present invention is a process forproducing a polymer, comprising polymerizing a methacrylic ester or anacrylic ester by the polymerization process (Y).

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1(A) is a GPC chart of an isoprene/n-butyl acrylate diblockcopolymer obtained finally in Example 10 according to the polymerizationprocess (X) of the present invention, and FIG. 1(B) is a GPC chart ofpolyisoprene prepared in a first step for producing this diblockcopolymer. Transverse axes represent retention time.

DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will be in detail described hereinafter.

[0031] A methacrylic ester or an acrylic ester which is a monomer in thepolymerization processes (X) and (Y) according to the present inventionis not limited to specified species [the above-mentioned ester may bereferred to as a “(meth)acrylic ester” hereinafter]. Thus, variousspecies thereof can be used. Specific examples of the methacrylic esterinclude esters of a primary alcohol and methacrylic acid, such as methylmethacrylate, ethyl methacrylate, propyl methacrylate, n-butylmethacrylate, isobutyl methacrylate, hexyl methacrylate, 2-ethylhexylmethacrylate, dodecyl methacrylate, lauryl methacrylate, methoxyethylmethacrylate, dimethylaminoethyl methacrylate, diethylaminoethylmethacrylate, glycidyl methacrylate, trimethoxysilylpropyl methacrylate,trifluoromethyl methacrylate, trifluoroethyl methacrylate; esters of asecondary alcohol and methacrylic acid, such as isopropyl methacrylate,cyclohexyl methacrylate and isobornyl methacrylate; and esters of atertiary alcohol and methacrylic acid, such as tert-butyl methacrylate.Specific examples of the acrylic ester include esters of a primaryalcohol and acrylic acid, such as methyl acrylate, ethyl acrylate,propyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate,2-ethylhexyl acrylate, dodecyl acrylate, lauryl acrylate, methoxyethylacrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate,glycidyl acrylate, trimethoxysilylpropyl acrylate, trifluoromethylacrylate, trifluoroethyl acrylate; esters of a secondary alcohol andacrylic acid, such as isopropyl acrylate, cyclohexyl acrylate andisobornyl acrylate; and esters of a tertiary alcohol and acrylic acid,such as tert-butyl acrylate. In the case that any one of esters of aprimary alcohol and methacrylic acid or acrylic acid is used out of theabove-mentioned (meth) acrylic esters, advantages of the presentinvention are in particular remarkably exhibited.

[0032] If necessary, as raw material or raw materials, one or more ofother anionic polymerizable monomers may be used together with the(meth)acrylic ester in the present invention. Examples of the anionicpolymerizable monomer that can be optionally used include methacrylic oracrylic monomers such as trimethylsilyl methacrylate,N-isopropylmethacrylamide, N-tert-butylmethacrylamide, trimethylsilylacrylate, N-isopropylacrylamide, and N-tert-butylacrylamide. Moreover,there may be used a multifunctional anionic polymerizable monomer havingin the molecule thereof two or more methacrylic or acrylic structures,such as methacrylic ester structures or acrylic ester structures (forexample, ethylene glycol diacrylate, ethylene glycol dimethacrylate,1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanedioldiacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropanetriacrylate and trimethylolpropane trimethacrylate).

[0033] In the polymerization processes (X) and (Y) according to thepresent invention, only one of the monomers, for example, the(meth)acrylic ester may be used, or two or more thereof may be used incombination. When two or more of the monomers may be used incombination, any copolymerization form selected from random, block,tapered block and the like copolymerization forms may be effected byselecting conditions such as a combination of the monomers and thetiming of adding the monomers to the polymerization system (for example,simultaneous addition of two or more monomers, or separate additions atintervals of a given time). The polymerization processes (X) and (Y) ofthe present invention are polymerization processes superior ininitiation efficiency and living polymerization property. Therefore,these processes exhibit particularly remarkable effects on blockcopolymerization.

[0034] First, the polymerization process (X) according to the presentinvention will be described.

[0035] In the polymerization process (X) according to the presentinvention, it is important to polymerize a (meth)acrylic ester

[0036] (A) in the presence of a tertiary organoaluminum compound havingin the molecule thereof a chemical structure represented by the formula:Al—O—Ar wherein Ar represents an aromatic ring,

[0037] (B) using a polymerization initiator compound comprising aproduct of an addition reaction of a conjugated diene compound and anorganic alkali metal compound. When both of the above-mentionedrequirements (A) and (B) are satisfied, the scopes of the (meth)acrylicester, the organic alkali metal compound and a solvent media forpolymerization that can be used become wide and cooling conditions uponthe polymerization can be made mild. Moreover, polymerization results(initiation efficiency and living polymerization property) can be madegood. The polymerization initiator compound used in the polymerizationprocess (X) of the present invention is a product obtained by additionreaction of a conjugated diene compound with an organic alkali metalcompound. Examples of the conjugated diene compound include1,3-butadiene, isoprene, myrcene, 2-methyl-1,3-pentadiene andcyclohexadiene. Among these compounds, 1,3-butadiene or isoprene ispreferred and 1,3-butadiene is particularly preferred in the view ofgood initiation efficiency.

[0038] As the organic alkali metal compound used in the polymerizationprocess (X) according to the present invention, there may be used anyalkali metal salt of an organic compound that can be nucleophilicallyadded to the conjugated diene compound. As the alkali metal atom whichthe organic alkali metal compound has, lithium, potassium or sodium ispreferred. Lithium is particularly preferred. Examples of the organicgroup corresponding to the moiety where one ore more alkali metal atomsare removed from the organic alkali metal compound include monovalent orpolyvalent saturated hydrocarbon groups, such as n-butyl, sec-butyl andtert-butyl; and monovalent or polyvalent aromatic hydrocarbon groups,such as diphenylmethyl, 1,1-diphenyl-3-methylpentyl, 1,1-diphenylhexyl,triphenylmethyl and fluorenyl. This organic group may be a group in theform of a polymer (in the specification, the word “polymer” includes theconception of an “oligomer”.). Therefore, the molecular weight thereofextends over a wide range and is not necessarily limited. In general,the molecular weight thereof ranges from 15 to 5,000,000. Typicalexamples of the monofunctional organic alkali metal compound among theorganic alkali metal compounds include low molecular weight organicmonolithium compounds having as an anionic center a primary carbon atom,such as n-butyllithium; low molecular weight organic monolithiumcompounds having as an anionic center a secondary carbon atom, such assec-butyllithium, diphenylmethyllithium and fluorenyllithium; lowmolecular weight organic monolithium compounds having as an anioniccenter a tertiary carbon atom, such as tert-butyllithium,1,1-diphenyl-3-methylpentyllithium, 1,1-diphenylhexyllithium,triphenylmethyllithium; monolithium salts of a polymer having a chemicalstructure wherein a lithium atom is bonded to only one terminal of itsmolecular chain, such as polystyryllithium andpoly-a-methylstyryllithium. Typical examples of the multifunctionalorganic alkali metal compound having in the molecule thereof two or morealkali metal atoms among the organic alkali metal compounds includeorganic dilithium compounds, such as tetra α-methylstyrenedilithium,1,3-bis(1-lithio-1,3-dimethylpentyl)benzene,1,3-bis(1-lithio-1-phenyl-3-methylpentyl)benzene; lithium salts of apolymer having a chemical structure wherein lithium atoms are bonded totwo or more terminals of its molecular chain, such as organicmultilithium compounds obtained by reacting a low molecular weightorganic monolithium compound with divinylbenzene (for example, acompound obtained by reacting sec-butyllithium as the low molecularweight organic monolithium compound with divinylbenzene in an amount of0.5 mole or more of the latter per mole of the former); and multilithiumsalts of a polymer having a chemical structure wherein each lithium atomis bonded in a pendant form to each of plural sites in the middle of itsmain chain, such as multilithium salts of a polymer obtained by reactinga polymer having in the molecule thereof two or more double bonds (forexample, a conjugated diene polymer) with a low molecular weight organicmonolithium compound (for example, sec-butyllithium) in an amount of 2or more moles of the latter per mole of the former in the presence of aLewis base (for example, N,N,N′,N′-tetramethylethylenediamine).

[0039] Among the above-mentioned low molecular weight organicmonolithium compounds, the low molecular weight organic monolithiumcompounds having as an anionic center a secondary carbon atom or aprimary carbon atom are preferred and sec-butyllithium andn-butyllithium are particularly preferred in view of high safety, goodhandling performance and high initiation efficiency.

[0040] As the lithium salt of a polymer having a chemical structurewherein a lithium atom or lithium atoms are bonded to one or moreterminals of its molecular chain, such as the lithium salt of a polymerhaving a chemical structure wherein a lithium atom is bonded to only oneterminal of its molecular chain or the lithium salt of a polymer havinga chemical structure wherein lithium atoms are bonded to two or moreterminals of its molecular chain, there may be used a so-called livingpolymer produced by anionic polymerization of an anionic polymerizablemonomer, using a low molecular weight organolithium compound as apolymerization initiator compound. In the case that the organolithiumcompound used as the polymerization initiator compound ismonofunctional, the resultant living polymer is basically a monolithiumsalt of a linear polymer. In the case that the organolithium compound ismultifunctional (bi- or more-functional), the resultant living polymeris basically a dilithium or multilithium salt of a linear or star-shapedpolymer. The anionic polymerizable monomer used to produce such a livingpolymer is not necessarily limited. Preferred are nonpolar or slightlypolar anionic polymerizable monomers, for example, aromatic vinylcompounds such as styrene, α-methylstyrene, p-methylstyrene andm-methylstyrene.

[0041] In the case that as the precursor (organic alkali metal compound)for preparing the polymerization initiator compound for polymerizing a(meth)acrylic ester, there is used the above-mentioned lithium salt of apolymer having a chemical structure wherein a lithium atom or lithiumatoms are bonded to one or more terminals of its molecular chain, thepolymer obtained through subsequent addition of a conjugated dienecompound and polymerization of the (meth)acrylic ester is a blockcopolymer. In the case that, as the precursor, there is used theabove-mentioned multilithium salt of a polymer having a chemicalstructure wherein each lithium atom is bonded in a pendant form to eachof plural sites in its main chain, the polymer obtained throughsubsequent addition of a conjugated diene compound and polymerization ofthe (meth)acrylic ester is a graft copolymer.

[0042] The polymerization initiator compound used in the polymerizationprocess (X) of a (meth)acrylic ester according to the present inventionis prepared by subjecting the above-mentioned conjugated diene compoundto addition reaction with the above-mentioned organic alkali metalcompound. The anionic center of the product resulting from such additionreaction is a carbon atom originating from the conjugated dienecompound. In the present invention, as the polymerization initiatorcompound for polymerizing a (meth)acrylic ester, the organic alkalimetal compound is not used as it is but the organic alkali compound isconverted to a product resulting from the addition reaction thereof withthe conjugated diene compound and then the product is used. By such useas well as addition of a tertiary organoaluminum compound having in themolecule thereof a chemical structure represented by the formula:Al—O—Ar wherein Ar represents an aromatic ring to the polymerizationsystem, the following advantages of the present invention can beattained: enlargement of the scope of the (meth)acrylic ester, theorganic alkali metal compound and the solvent media for polymerizationthat can be used; making cooling conditions mild upon thepolymerization; and an improvement in polymerization results (initiationefficiency and living polymerization property).

[0043] In the polymerization process (X) according to the presentinvention, reaction conditions at the time of the addition reaction of aconjugated diene compound with an organic alkali metal compound are notnecessarily limited. In general, however, the conjugated diene compoundis used in an amount of 1 mole or more per mole of the alkali metal atom(or anionic center) of the organic alkali metal compound. In order tomake addition of the anionic center of the organic alkali metal compoundto the conjugated diene compound more complete, the conjugated dienecompound is preferably used in an amount of 2 moles or more per mole ofthe alkali metal atom (or anionic center) of the organic alkali metalcompound. The upper limit of the use ratio of the conjugated dienecompound to the organic alkali metal compound is not limited in order toattain the advantages of the present invention. However, as the useratio of the conjugated diene compound to the organic alkali metalcompound becomes larger, the chain of a poly(conjugated diene compound)resulting from the anionic polymerization of the conjugated dienecompound becomes longer. Therefore, this ratio is preferably set to anappropriate value, considering the chemical structure of a targetpolymer. That is, in order to obtain a block copolymer or a graftcopolymer comprising a polymer fragment comprising the conjugated dienecompound and a polymer fragment comprising the (meth)acrylic ester, theratio of the conjugated diene compound to the organic alkali metalcompound is preferably set, considering the polymerization degree of theconjugated diene compound in the target copolymer, and the like. If itis not desired to introduce any polymer fragment comprising theconjugated diene compound into a final target polymer, it is preferredto adopt such a condition that the use ratio of the conjugated dienecompound to the organic alkali metal compound is not raised very much(for example, a condition of 50 moles or less per mole of the alkalimetal atom (or anionic center) of the organic alkali metal compound).

[0044] The reaction of a conjugated diene compound with an organicalkali metal compound is not necessarily limited. Preferably, thereaction is conducted in an organic solvent. The organic solvent is notnecessarily limited. The following are preferably used since safety uponhandling is relatively high and they can also be used as an organicsolvent upon the subsequent polymerization of a (meth)acrylic ester:aromatic hydrocarbon solvents such as benzene, toluene, ethylbenzene andxylene; saturated hydrocarbon solvents such as hexane, cyclohexane andmethylcyclohexane; halogenated hydrocarbon solvents such as chloroform,methylene chloride and carbon tetrachloride; ester solvents such asdimethyl phthalate; and the like. These organic solvents may be usedalone or in combination of two or more. In the case that the organicsolvent is used, the amount thereof may be appropriately adjusteddependently on the kind of the used organic alkali metal compound, themolecular weight of a target polymerization initiator compound, the kindof the organic solvent, and the like. In general, from the standpoint ofsmooth advance of the reaction, the organic solvent is preferably usedin an amount of 200 to 3000 parts by weight per 100 parts by weight ofthe total of the organic alkali metal compound and the conjugated dienecompound.

[0045] In the reaction of a conjugated diene compound with an organicalkali metal compound in the polymerization process (X) according to thepresent invention, it is desired that incorporation of water contentinto the reaction system is avoided as much as possible. Therefore, itis preferred to use, as chemical substances that are supplied to thesystem, such as the conjugated diene compound and any other chemicalsubstance (for example, an organic solvent), substances that containswater content as less as possible. If necessary, therefore, they may besubjected to deaeration or dehydration treatment. The reaction ispreferably conducted under the atmosphere of an inert gas such asnitrogen, argon or helium.

[0046] Furthermore, in order to make reaction conditions in the reactionsystem uniform, for example, the addition reaction is conducted withvigorous stirring.

[0047] In the reaction of an organic alkali metal compound with aconjugated diene compound in the polymerization process (X) according tothe present invention, the temperature in the reaction system is notlimited. An appropriate temperature may be selected and adopteddependently on the kind of the organic alkali metal compound, the kindof the conjugated diene compound, and the like. In many cases, however,it is preferred to adopt a temperature within the range of −20 to 100°C. This reaction may be allowed to continue until the addition of theconjugated diene compound completes while the situation of the advanceof the reaction is checked by a change in color originating from theanions in the reaction system or quantitative analysis of a samplecollected from the reaction system by an analysis method such as gaschromatography or a nuclear magnetic resonance absorption spectrum(NMR). Usually, the time necessary for the reaction is within the rangeof 1 minute to 24 hours.

[0048] In the polymerization process (X) according to the presentinvention, a tertiary organoaluminum compound having in the moleculethereof a chemical structure represented by the formula: Al—O—Ar whereinAr represents an aromatic ring (which may be referred to as an“organoaluminum compound (I)” hereinafter) is caused to be present inthe polymerization system at least in the step of polymerizing a(meth)acrylic ester. By selecting and using the organoaluminum compound(I) as an organoaluminum compound which is caused to be present in thesystem for polymerizing the (meth)acrylic ester as well as the use ofthe polymerization initiator compound comprising an addition reactionproduct of the organic alkali metal compound and the conjugated dienecompound, the following advantages of the present invention can beattained in the polymerization process (X) according to the presentinvention: enlargement of the scope of the (meth)acrylic ester, theorganic alkali metal compound and the solvent media for polymerizationthat can be used; making cooling conditions mild upon thepolymerization; and an improvement in polymerization results (initiationefficiency and living polymerization property).

[0049] The organoaluminum compound (I) is roughly classified into thefollowing three kinds: an organoaluminum compound having a chemicalstructure wherein only one out of three bonds that an aluminum atom hasis connected to an aromatic ring through an oxygen atom (which may bereferred to as an organoaluminum compound (I-1) hereinafter); anorganoaluminum compound having a chemical structure wherein two out ofthree bonds that an aluminum atom has are connected to an aromatic ringthrough an oxygen atom (which may be referred to as an organoaluminumcompound (I-2) hereinafter); and an organoaluminum compound having achemical structure wherein three out of three bonds that an aluminumatom has are connected to an aromatic ring through an oxygen atom (whichmay be referred to as an organoaluminum compound (I-3) hereinafter).

[0050] A typical chemical structure of the organoaluminum compound (I-2)or (I-3) is represented by the following general formula (A):

AlR¹R²R³  (A)

[0051] wherein R¹ represents a monovalent saturated hydrocarbon groupwhich may have a substituent, a monovalent aromatic hydrocarbon groupwhich may have a substituent, an alkoxyl group which may have asubstituent, an aryloxy group which may have a substituent, orN,N-disubstituted amino group; and R² and R³ each independentlyrepresents an aryloxy group which may have a substituent, or R² and R³may be bonded to each other to form an arylenedioxy group which may havea substituent.

[0052] A typical chemical structure of the organoaluminum compound (I-1)is represented by the following general formula (B):

AlR⁴R⁵R⁶  (B)

[0053] wherein R⁴ represents an aryloxy group which may have asubstituent; and R⁵ and R⁶ each independently represents a monovalentsaturated hydrocarbon group which may have a substituent, a monovalentaromatic hydrocarbon group which may have a substituent, an alkoxylgroup which may have a substituent, or N,N-disubstituted amino group.

[0054] As the organoaluminum compound (I), a preferred compound isappropriately selected and used, dependently on the kinds of themonomers, for example, the (meth)acrylic ester to be used, and the like.The above-mentioned organoaluminum compound (I-2) or (I-3) is morepreferred in view of high polymerization rate, high initiationefficiency, high living polymerization property, a mild coolingcondition upon the polymerization, and the like.

[0055] Examples of the aryloxy group that may have a substituent, whichcan be represented by R¹, R², R³ or R⁴ in the general formulae (A) and(B), include aryloxy groups having no substituent, such as phenoxy,2-methylphenoxy, 4-methylphenoxy, 2,6-dimethylphenoxy,2,4-di-tert-butylphenoxy, 2,6-di-tert-butylphenoxy,2,6-di-tert-butyl-4-methylphenoxy, 2,6-di-tert-butyl-4-ethylphenoxy,2,6-diphenylphenoxy, 1-naphthoxy, 2-naphthoxy, 9-phenanthryloxy and1-pyrenyloxy groups; and aryloxy groups having a substitutent, such as a7-methoxy-2-naphthoxy group. Among the aryloxy groups that may have asubstituent, preferred are substituted phenoxy groups wherein alkylgroups are bonded to 2- and 6-positions thereof (for example,2,6-dimethylphenoxy, 2,6-di-tert-butylphenoxy,2,6-di-tert-butyl-4-methylphenoxy, and 2,6-di-tert-butyl-4-ethylphenoxygroups). More preferred are phenoxy groups wherein branched alkyl groupsare bonded to 2- and 6-positions thereof (so-called hindered phenoxygroups, for example, 2,6-di-tert-butylphenoxy,2,6-di-tert-butyl-4-methylphenoxy, and 2,6-di-tert-butyl-4-ethylphenoxygroups).

[0056] Examples of the arylenedioxy group that may have a substituent,which can be formed by bonding R² and R³ to each other in the generalformula (A), include groups wherein hydrogen atoms of two phenolichydroxyl groups are removed from 2,2′-biphenol, 2,2′-methylenebisphenol,2,2′-methylenebis(4-methyl-6-tert-butylphenol),(R)-(+)-1,1′-bi-2-naphthol, (S)-(−)-1,1′-bi-2-naphthol or the like.

[0057] Concerning the aryloxy group which may have a substituent or thearylenedioxy group which may have a substituent, this substituent may beat least one substituent. In this case, examples of the substituentinclude alkoxy groups such as a methoxy group, an ethoxy group, anisopropoxy group and a tert-butoxy group, and halogen atoms such aschlorine and bromine.

[0058] Examples of the monovalent saturated hydrocarbon group that mayhave a substituent, which can be each independently represented by R¹,R⁵ and R⁶ in the general formulae (A) and (B), include alkyl groups suchas methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,tert-butyl, 2-methylbutyl, 3-methylbutyl, n-octyl, and 2-ethylhexylgroups; and cycloalkyl groups such as a cyclohexyl group. Examples ofthe monovalent aromatic hydrocarbon group that may have a substituent,which can be each independently represented by R¹, R⁵ and R⁶, includearyl groups such as a phenyl group; and aralkyl groups such as a benzylgroup. Examples of the alkoxy group that may have a substituent, whichcan be each independently represented by R¹, R⁵ and R⁶, include methoxy,ethoxy, isopropoxy, and tert-butoxy groups. Examples of theN,N-disubstituted amino group, which can be each independentlyrepresented by R¹, R⁵ and R⁶, include dialkylamino groups such asdimethylamino, diethylamino and diisopropylamino groups; and abis(trimethylsilyl)amino group. Examples of the substituent which eachof the monovalent saturated hydrocarbon group, the monovalent aromatichydrocarbon group, the alkoxy group and the N,N-disubstituted aminogroup may have include alkoxy groups such as methoxy, ethoxy, isopropoxyand tert-butoxy groups; and halogen atoms such as chlorine and bromine.

[0059] R¹, R² and R³ in the general formula (A) may have the samechemical structure or different chemical structures if they are withinthe above-defined scope. In the same way, R⁵ and R⁶ in the generalformula (B) may have the same chemical structure or different chemicalstructures if they are within the above-defined scope.

[0060] Typical examples of the organoaluminum compound represented bythe general formula (A) includeethylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum,ethylbis(2,6-di-tert-butylphenoxy)aluminum,ethyl[2,2′-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum,isobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum,isobutylbis(2,6-di-tert-butylphenoxy)aluminum,isobutyl[2,2′-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum,n-octylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum,n-octylbis(2,6-di-tert-butylphenoxy)aluminum,n-octyl[2,2′-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum,methoxybis(2,6-di-tert-butyl-4-methylphenoxy)aluminum,methoxybis(2,6-di-tert-butylphenoxy)aluminum,methoxy[2,2′-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum,ethoxybis(2,6-di-tert-butyl-4-methylphenoxy)aluminum,ethoxybis(2,6-di-tert-butylphenoxy)aluminum,ethoxy[2,2′-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum,isopropoxybis(2,6-di-tert-butyl-4-methylphenoxy)aluminum,isopropoxybis(2,6-di-tert-butylphenoxy)aluminum,isopropoxy[2,2′-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum,tert-butoxybis(2,6-di-tert-butyl-4-methylphenoxy)aluminum,tert-butoxy(2,6-di-tert-butylphenoxy)aluminum,tert-butoxy[2,2′-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum,tris(2,6-di-tert-butyl-4-methylphenoxy)aluminum, andtris(2,6-diphenylphenoxy)aluminum. Among these organoaluminum compoundsrepresented by the general formula (A),isobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum,isobutylbis(2,6-di-tert-butylphenoxy)aluminum,isobutyl[2,2′-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum andthe like are especially preferred from the viewpoints of highpolymerization initiation efficiency, high living polymerizationproperty, easiness of acquisition and handling, and the like.

[0061] Typical examples of the organoaluminum compound represented bythe general formula (B) includediethyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum,diethyl(2,6-di-tert-butylphenoxy)aluminum,diisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum,diisobutyl(2,6-di-tert-butylphenoxy)aluminum,di-n-octyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum, anddi-n-octyl(2,6-di-tert-butylphenoxy)aluminum.

[0062] The process for producing the organoaluminum compound (I) is notespecially limited. The compound (I) can be produced, for example,according to any known process.

[0063] In the polymerization process (X) according to the presentinvention, only one of the organoaluminum compounds (I) may be used, ortwo or more thereof may be used in combination.

[0064] The amount of the organoaluminum compound (I) in thepolymerization process (X) according to the present invention may beappropriately selected dependently on the kind of polymerizationoperation, the kind of a solvent constituting a polymerization systemwhen solution polymerization is performed, other various polymerizationconditions, and the like. In general, the organoaluminum compound (I) isused in an amount of preferably 1 mole or more and more preferably 2 to100 moles per mole of the alkali metal atom (or anionic center) of theused polymerization initiator compound. In the case that the organicalkali metal compound and the conjugated diene compound are used toprepare a polymerization initiator compound and then the substantiallytotal amount of the polymerization initiator compound is used topolymerize a (meth)acrylic ester, the mole number of the alkali metalatom (or anionic center) of the used organic alkali metal compound issubstantially the same as the mole number of the alkali metal atom (oranionic center) of the prepared polymerization initiator compound.Therefore, the organoaluminum compound (I) is used in an amount ofpreferably 1 mole or more and more preferably 2 to 100 moles per mole ofthe alkali metal atom (or anionic center) of the initially used organicalkali metal compound.

[0065] In the polymerization reaction in the polymerization process (X)according to the present invention, the following may be caused to bepresent in the polymerization system if desired: an ether compound; atertiary polyamine compound; an inorganic salt such as lithium chloride;a metal alkoxide compound such as lithium methoxyethoxyethoxide orpotassium tert-butoxide; or an organic quaternary salt such astetraethylammonium chloride or tetraethylphosphonium bromide. In thecase that the above-mentioned ether compound or the above-mentionedtertiary polyamine compound is caused to be present, it is possible toimprove initiation efficiency (or block efficiency) and polymerizationrate still more and further improve living polymerization property stillmore by suppressing inactivation in the polymerization of a(meth)acrylic ester. Thus, this case is preferred.

[0066] The above-mentioned ether compound can be appropriately selectedfrom compounds which have in the molecule thereof an ether bond (—O—)and do not comprise any metal component and be used so far as thecompounds do not have an adverse effect on polymerization reaction.Preferably, the ether compound is selected from cyclic ether compoundshaving in the molecule thereof two or more ether bonds and acyclic ethercompounds having in the molecule thereof one or more ether bonds fromthe viewpoints of high effects such as high polymerization initiationefficiency and high living polymerization property upon polymerization.Specific examples of the cyclic ether compound having in the moleculethereof two or more ether bonds include crown ethers such as 12-crown-4,15-crown-5 and 18-crown-6. Specific examples of the acyclic ethercompound having in the molecule thereof one or more ether bonds includeacyclic monoether compounds such as dimethyl ether, diethyl ether,diisopropyl ether, dibutyl ether and anisol; acyclic diether compoundssuch as 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-diisopropoxyethane,1,2-dibutoxyethane, 1,2-diphenoxyethane, 1,2-dimethoxypropane,1,2-diethoxypropane, 1,2-diisopropoxypropane, 1,2-dibutoxypropane,1,2-diphenoxypropane, 1,3-dimethoxypropane, 1,3-diethoxypropane,1,3-diisopropoxypropane, 1,3-dibutoxypropane, 1,3-diphenoxypropane,1,4-dimethoxybutane, 1,4-diethoxybutane, 1,4-diisopropoxybutane and1,4-dibutoxybutane, 1,4-diphenoxybutane; acyclic triether compounds suchas diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether,dibutylene glycol dimethyl ether, diethylene glycol diethyl ether,dipropylene glycol diethyl ether and dibutylene glycol diethyl ether;dialkyl ethers of polyalkylene glycols such as triethylene glycoldimethyl ether, tripropylene glycol dimethyl ether, tributylene glycoldimethyl ether, triethylene glycol diethyl ether, tripropylene glycoldiethyl ether, tributylene glycol diethyl ether, tetraethylene glycoldimethyl ether, tetrapropylene glycol dimethyl ether, tetrabutyleneglycol diethyl ether, tetraethylene glycol diethyl ether, tetrapropyleneglycol diethyl ether and tetrabutylene glycol diethyl ether. Among theabove-mentioned specific examples of the ether compounds, the acyclicether compounds are preferred, and diethyl ether and 1,2-dimethoxyethaneare especially preferred since they have a little adverse effect on theorganoaluminum compound (I), they exhibit the effect of improvements inpolymerization rate, living polymerization property, initiationefficiency (or block efficiency) and so on especially remarkably andthey can easily be obtained.

[0067] If the cyclic ether compound having in the molecule thereof oneether bond, for example, tetrahydrofuran or such an epoxy compound aspropyleneoxide, is caused to be present in the polymerization systemaccording to the present invention, the ether compound may interact withthe organoaluminum compound (I) too strongly or react directly with thepolymerization initiator compound or the living polymer that is growing.In such a case, it is generally preferred to avoid the manner that thecyclic ether compound is caused to be present in the polymerizationsystem at least in the polymerization step of a (meth)acrylic ester.

[0068] The tertiary polyamine compound can be appropriately selectedfrom compounds having in the molecule thereof two or more tertiary aminestructures and be used so far as the compounds do not have an adverseeffect on the polymerization reaction. The “tertiary amine structure” inthe present invention means a partial chemical structure wherein threecarbon atoms are bonded to one nitrogen atom, and may constitute a partof an aromatic ring so far as one nitrogen atom is bonded to threecarbon atoms. Preferred specific examples of the tertiary polyaminecompound include chain-form polyamine compounds such asN,N,N′,N′-tetramethylethylenediamine,N,N,N′,N′-tetraethylethylenediamine,N,N,N′,N″,N″-pentamethyldiethylenetriamine,1,1,4,7,10,10-hexamethyltriethylenetetraamine andtris[2-(dimethylamino)ethyl]amine; non-aromatic heterocyclic compoundssuch as 1,3,5-trimethylhexahydro-1,3,5-triazine,1,4,7-trimethyl-1,4,7-triazacyclononaneo, and1,4,7,10,13,16-hexamethyl-1,4,7,10,13,16-hexaazacyclooctadecane; andaromatic heterocyclic compounds such as 2,2′-bipyridyl and2,2′:6′,2″-terpyridine. In the case that a tertiary monoamine compoundsuch as triethylamine is caused to be present in the polymerizationsystem at least in the polymerization step of a (meth)acrylic ester,advantages are hardly produced or only small advantages are produced.

[0069] Any compound having in the molecule thereof one or more etherbonds and one tertiary amine structure can be regarded as theabove-mentioned ether compound. Any compound having in the moleculethereof one or more ether bonds and two or one tertiary amine structurescan be regarded as either the above-mentioned ether compound or theabove-mentioned tertiary polyamine compound. Therefore, any compoundhaving in the molecule thereof one or more ether bonds and one or moretertiary amine structures can be used as the ether compound or tertiarypolyamine compound.

[0070] In the case that the above-mentioned ether compound or tertiarypolyamine compound is used, the amount thereof is not necessarilylimited. In order to exhibit sufficiently the above-mentioned advantagesbased on the addition thereof, the total mole number of the used ethercompound and the tertiary polyamine compound is preferably 0.1 time ormore, more preferably 0.3 time or more, and still more preferably 0.5time or more the mole number of the alkali metal atom or anionic centerof the used polymerization initiator compound or a precursor thereof(for example, an organic alkali metal compound). The upper limit of theamount of the ether compound and the tertiary polyamine compound is notnecessarily limited. However, if the amount thereof is too large,initiation efficiency trends to drop. Therefore, in order that theinitiation efficiency does not drop very much, it is generally preferredto set the total amount of the ether compound and the tertiary polyaminecompound to about 95% or less by weight of the polymerization system.

[0071] In the polymerization reaction in the polymerization process (X)according to the present invention, any polymerization manner, forexample, solution polymerization, bulk polymerization or precipitationpolymerization, can be adopted. Since the temperature of thepolymerization can be controlled and conditions can be made uniform inthe polymerization system to advance the polymerization smoothly, it ispreferred to adopt solution polymerization in an organic solvent. Thekind of the organic solvent is not necessarily limited. There ispreferably used an aromatic hydrocarbon solvent such as benzene,toluene, ethylbenzene or xylene; a saturated hydrocarbon solvent such ashexane, cyclohexane, or methylcyclohexane; a halogenated hydrocarbonsolvent such as chloroform, methylene chloride or carbon tetrachloride;an ester solvent such as dimethyl phthalate; or the like in view ofrelatively high safety on handling thereof, less incorporation intowaste liquid, and easy recovery and purification thereof. These organicsolvents may be used alone or in combination of two or more.

[0072] In the case that the organic solvent is used, the amount thereofmay be appropriately adjusted, dependently on the polymerization degreeof a target polymer, the kinds of the monomers, for example, the(meth)acrylic ester, the kind of the polymerization initiator compound,the kind of the organoaluminum compound (I), the kind of the organicsolvent, and the like. In general, the organic solvent is used in anamount of 200 to 3000 parts by weight per 100 parts by weight of thetotal of the polymerization initiator compound and the monomers.

[0073] In the polymerization reaction in the polymerization process (X)according to the present invention, it is desired that incorporation ofwater content into the polymerization system is avoided as much aspossible. Therefore, it is preferred that, as chemical substances thatare supplied to the system, such as the monomers, the organoaluminumcompound (I), any other chemical substance (for example, the organicsolvent, the ether compound, the tertiary polyamine compound and thelike), substances that contains water content as less as possible areused. If necessary, therefore, they may be subjected to deaeration ordehydration treatment. The polymerization reaction is preferablyconducted under the atmosphere of an inert gas such as nitrogen, argonor helium.

[0074] Furthermore, in order to make reaction conditions in thepolymerization reaction system uniform, for example, the polymerizationis conducted with vigorous stirring.

[0075] In general, the polymerization process (X) according to thepresent invention comprises an operation of addition reaction of aconjugated diene compound with an organic alkali metal compound toprepare a polymerization initiator compound, and an operation ofpolymerization of the (meth) acrylic ester with the polymerizationinitiator compound.

[0076] The manner of the polymerization reaction in the polymerizationprocess (X) according to the present invention is not necessarilylimited. Conveniently, a conjugated diene compound is reacted with anorganic alkali metal compound to prepare a polymerization initiatorcompound, and next a (meth)acrylic ester is added to this system. Thetiming of adding an organoaluminum compound (I) at this time is notnecessarily limited so far as the organoaluminum compound (I) can bepresent in the polymerization system of the (meth)acrylic ester. Anappropriate method can be adopted from the following various methods: amethod comprising adding the total amount of an organoaluminum compound(I) to the system containing a polymerization initiator compound beforeaddition of a (meth)acrylic ester; a method comprising mixing the totalamount of an organoaluminum compound (I) with a (meth) acrylic ester soas to add the organoaluminum compound (I) together with the(meth)acrylic ester to the system containing a polymerization initiatorcompound; a method comprising mixing a part of an organoaluminumcompound (I) with a (meth) acrylic ester and then adding the remainderof the organoaluminum compound (I) to the system containing apolymerization initiator compound so as to add the part of theorganoaluminum compound (I) together with the (meth) acrylic ester tothe system containing the polymerization initiator compound and theremainder of the organoaluminum compound (I); and the like. Among theabove-mentioned methods of adding an organoaluminum compound (I), themethod comprising mixing at least one part of an organoaluminum compound(I) with a (meth)acrylic ester and then adding the resultant mixture tothe polymerization system is preferred since advantages as follows canbe produced: a side reaction based on coordination of the organoaluminumcompound (I) to the (meth)acrylic ester is suppressed; and inactivationof the polymerization initiator compound based on a reaction of theorganoaluminum compound (I) with an impurity in the (meth)acrylic esteris suppressed.

[0077] When an organoaluminum compound (I) is brought into contact witha polymerization initiator compound, in order to raise initiationefficiency of the polymerization initiator compound, the temperature inthe reaction system is preferably controlled to 40° C. or lower and ismore preferably controlled to 25° C. or lower.

[0078] In the case that polymerization reaction of a (meth)acrylic esteris conducted in the presence of an ether compound or a tertiarypolyamine compound, the timing of adding the ether compound or thetertiary polyamine compound is not necessarily limited. Preferably,there is used such a manner that the ether compound or the tertiarypolyamine compound can be brought into contact with an organoaluminumcompound (I) before being brought into contact with a polymerizationinitiator compound.

[0079] The following will describe the polymerization process (Y)according to the present invention.

[0080] In the polymerization process (Y) according to the presentinvention, it is important to polymerize a (meth)acrylic ester,

[0081] (C) using a polymerization initiator compound comprising aproduct of an addition reaction of a compound having a1,1-diaryl-1-alkene structure (which may be hereinafter referred to as a“diarylalkene type compound”) and an organic alkali metal compound,

[0082] (D) by adding, to the polymerization system, the (meth)acrylicester in the form of a mixture with a tertiary organoaluminum compoundhaving in the molecule thereof a chemical structure represented by theformula: Al—O—Ar wherein Ar represents an aromatic ring (anorganoaluminum compound (I)).

[0083] When the above-mentioned requirements (C) and (D) are satisfied,the scopes of the (meth)acrylic ester, the organic alkali metal compoundand a solvent media for polymerization that can be used become wide andcooling conditions upon the polymerization can be made mild. Moreover,polymerization results (initiation efficiency and living polymerizationproperty) can be made good. The polymerization initiator compound usedin the polymerization process (Y) of the present invention is a productobtained by addition reaction of a diarylalkene type compound with anorganic alkali metal compound. This diarylalkene type compound is acompound having, as a part of the molecule thereof, a chemical structurerepresented by the following formula:

[0084] wherein Ar1 and Ar2 each independently represents an aromaticring. Examples of the diarylalkene type compound include1,l-diaryl-1-alkene such as 1,1-diphenylethylene,1,1-bis(4-methylphenyl)ethylene, and 1,1-diphenylpropene; andbis(1-aryl-1-alkenyl)arene such as 1,3-bis(1-phenylethenyl) benzene.Among these compounds, particualrly preferred are 1,1-diphenylethyleneand 1,3-bis(l-phenylethenyl)benzene in view of superior initiationefficiency.

[0085] As the organic alkali metal compound, there may be used any oneof alkali metal salts of an organic compound that can benucleophilically added to the diarylalkene type compound. As the alkalimetal atom which the organic alkali metal compound has, lithium,potassium or sodium is preferred. Lithium is particularly preferred.Examples of the organic group corresponding to the moiety that one oremore alkali metal atoms are removed from the organic alkali metalcompound include monovalent or polyvalent saturated hydrocarbon groups,such as n-butyl, sec-butyl and tert-butyl; and monovalent or polyvalentaromatic hydrocarbon groups, such as benzyl, methylbenzyl and1-phenyl-1-methylethyl. The organic group may be a group in the form ofa polymer (in the specification, the word “polymer” includes theconception of an “oligomer”.). Therefore, the molecular weight thereofextends over a wide range and is not necessarily limited. In general,the molecular weight thereof ranges from 15 to 5,000,000. Typicalexamples of the monofunctional organic alkali metal compound among theorganic alkali metal compounds include low molecular weight organicmonolithium compounds having as an anionic center a primary carbon atom,such as n-butyllithium or benzyllithium; low molecular weight organicmonolithium compounds having as an anionic center a secondary carbonatom, such as sec-butyllithium and α-methyllithium; low molecular weightorganic monolithium compounds having as an anionic center a tertiarycarbon atom, such as tert-butyllithium and1-phenyl-1-methylethyllithium; monolithium salts of a polymer having achemical structure wherein a lithium atom is bonded to only one terminalof its molecular chain, such as polystyryllithium,poly-α-methylstyryllithium, polybutadienyllithium andpolyisoprenyllithium. In the case that such a monolithium salt isreacted in a sufficient amount with such a 1,1-diaryl-1-alkene as above,the resultant polymerization initiator is monofunctional. In the casethat such a monolithium salt is reacted in a sufficient amount with sucha bis(1-aryl-1-alkenyl)arene as above, the resultant polymerizationinitiator is bifunctional. Typical examples of the multifunctionalorganic alkali metal compound having in the molecule thereof two or morealkali metal atoms among the organic alkali metal compounds includeorganic dilithium compounds, such as tetra α-methylstyrenedilithium, and1,3-bis(1-lithio-1,3-dimethylpentyl)benzene; lithium salts of a polymerhaving a chemical structure wherein lithium atoms are bonded to two ormore terminals of its molecular chain, such as organic multilithiumcompounds obtained by reacting a low molecular weight organicmonolithium compound with divinylbenzene (for example, a compoundobtained by reacting sec-butyllithium as the low molecular weightorganic monolithium compound with divinylbenzene in an amount of 0.5mole or more of the latter per mole of the former); and multilithiumsalts of a polymer having a chemical structure wherein each lithium atomis bonded in a pendant form to each of plural sites in its main chain,such as multilithium salts of a polymer obtained by reacting a polymerhaving in the molecule thereof two or more double bonds (for example, aconjugated diene polymer) with a low molecular weight organicmonolithium compound (for example, sec-butyllithium) in an amount of 2or more moles of the latter per mole of the former in the presence of aLewis base (for example, N,N,N′,N′-tetramethylethylenediamine).

[0086] Among the above-mentioned low molecular weight organicmonolithium compounds, the low molecular weight organic monolithiumcompounds having as an anionic center a secondary carbon atom or aprimary carbon atom are preferred and sec-butyllithium andn-butyllithium are particularly preferred in view of high safety, goodhandling performance and high initiation efficiency.

[0087] As the lithium salt of a polymer having a chemical structurewherein a lithium atom or lithium atoms are bonded to one or moreterminals of its molecular chain, such as the lithium salt of a polymerhaving a chemical structure wherein a lithium atom is bonded to only oneterminal of its molecular chain or the lithium salt of a polymer havinga chemical structure wherein lithium atoms are bonded to two or moreterminals of its molecular chain, there may be used a so-called livingpolymer produced by anionic polymerization of an anionic polymerizablemonomer, using a low molecular weight organolithium compound as apolymerization initiator compound. In the case that the organolithiumcompound used as the polymerization initiator compound ismonofunctional, the resultant living polymer is basically a monolithiumsalt of a linear polymer. In the case that the organolithium compound ismultifunctional (bi- or more-functional), the resultant living polymeris basically a dilithium or multilithium salt of a linear or star-shapedpolymer. The anionic polymerizable monomer used to produce such a livingpolymer is not necessarily limited. Preferred are nonpolar or slightlypolar anionic polymerizable monomers, for example, aromatic vinylcompounds (from which diarylalkene type compounds are removed), such asstyrene, α-methylstyrene, p-methylstyrene, m-methylstyrene; andconjugated diene compounds, such as 1,3-butadiene, isoprene, myrcene,2-methyl-1,3-pentadiene and cyclohexadiene.

[0088] In the case that as a precursor (organic alkali metal compound)for preparing the polymerization initiator compound for polymerizing a(meth)acrylic ester, there is used the above-mentioned lithium salt of apolymer having a chemical structure wherein a lithium atom or lithiumatoms are bonded to one or more terminals of its molecular chain, thepolymer obtained through subsequent addition of a diarylalkene typecompound and polymerization of the (meth)acrylic ester is a blockcopolymer. In the case that as the precursor, there is used theabove-mentioned multilithium salt of a polymer having a chemicalstructure wherein each lithium atom is bonded in a pendant form to eachof plural sites in the middle of its main chain, the polymer obtainedthrough subsequent addition of a diarylalkene type compound andpolymerization of the (meth)acrylic ester is a graft copolymer.

[0089] The polymerization initiator compound used in the polymerizationprocess (Y) of a (meth)acrylic ester according to the present inventionis prepared by subjecting the above-mentioned diarylalkene type compoundto addition reaction with the above-mentioned organic alkali metalcompound. The anionic ion center of the product resulting from theaddition reaction is a carbon atom originating from the diarylalkenetype compound. In polymerization process (Y) according to the presentinvention, as the polymerization initiator compound for polymerizing a(meth)acrylic ester, the organic alkali metal compound is not used as itis but the organic alkali compound is converted to a product resultingfrom the addition reaction thereof with the diarylalkene type compoundand then the product is used. By such use and addition of the (meth)acrylic ester in the form of a mixture of this ester and theorganoaluminum compound (I) to the polymerization system, the followingadvantages of the present invention can be attained: enlargement of thescope of the (meth)acrylic ester, the organic alkali metal compound andthe solvent media for polymerization that can be used; making coolingconditions upon the polymerization mild; and an improvement inpolymerization results (initiation efficiency and living polymerizationproperty).

[0090] In the polymerization process (Y) according to the presentinvention, reaction conditions at the time of the addition reaction of adiarylalkene type compound with an organic alkali metal compound are notnecessarily limited. In general, however, the diarylalkene type compoundis used in an amount of 1 mole or more per mole of the alkali metal atom(or anionic center) of the organic alkali metal compound. In order tomake addition of the anionic center of the organic alkali metal compoundto the diarylalkene type compound more complete, the diarylalkene typecompound is preferably used in an excessive amount over the alkali metalatom (or anionic center) of the organic alkali metal compound. The upperlimit of the use ratio of the diarylalkene type compound to the organicalkali metal compound is not limited in order to attain the advantagesof the present invention. In general, however, the diarylalkene typecompound cannot be polymerized solely. Alternatively, even if it ispolymerized, the polymerizability is very low. In general, therefore, anexcessive amount of the diarylalkene type compound does not react andremains in the polymerization system. For this reason, considering adrop in productivity on the basis of recovery of the unreacteddiarylalkene type compound after the polymerization, the amount of thediarylalkene type compound is preferably 1000 moles or less and morepreferably 100 moles or less per mole of the alkali metal atom (or theanionic center) of the organic alkali metal compound.

[0091] The reaction of a diarylalkene type compound with an organicalkali metal compound is not necessarily limited. Preferably, thereaction is conducted in an organic solvent. The organic solvent is notnecessarily limited. The following are preferably used since safety uponhandling is relatively high and they can also be used as an organicsolvent upon subsequent polymerization of a (meth)acrylic ester:aromatic hydrocarbon solvents such as benzene, toluene, ethylbenzene andxylene; saturated hydrocarbon solvents such as hexane, cyclohexane andmethylcyclohexane; halogenated hydrocarbon solvents such as chloroform,methylene chloride and carbon tetrachloride; ester solvents such asdimethyl phthalate; and the like. These organic solvents may be usedalone or in combination of two or more. In the case that the organicsolvent is used, the amount thereof may be appropriately adjusteddependently on the kind of the used organic alkali metal compound, themolecular weight of a target polymerization initiator compound, the kindof the organic solvent, and the like. In general, from the standpoint ofsmooth advance of the reaction, the organic solvent is preferably usedin an amount of 200 to 3000 parts by weight per 100 parts by weight ofthe total of the organic alkali metal compound and the diarylalkene typecompound.

[0092] In the reaction of a diarylalkene type compound with an organicalkali metal compound in the polymerization process (Y) according to thepresent invention, it is desired that incorporation of water contentinto the reaction system is avoided as much as possible. Therefore, itis preferred to use, as chemical substances that are supplied to thesystem, such as the diarylalkene type compound and any other chemicalsubstance (for example, the organic solvent), substances that containswater content as less as possible. If necessary, therefore, they may besubjected to deaeration or dehydration treatment. The reaction ispreferably conducted under the atmosphere of an inert gas such asnitrogen, argon or helium.

[0093] Furthermore, in order to make reaction conditions in the reactionsystem uniform, for example, the addition reaction is conducted withvigorous stirring.

[0094] In the reaction of an organic alkali metal compound with adiarylalkene type compound in the polymerization process (Y) accordingto the present invention, the temperature in the reaction system is notlimited. An appropriate temperature may be selected and adopteddependently on the kind of the organic alkali metal compound, the kindof the diarylalkene type compound, and the like. In many cases, however,it is preferred to adopt a temperature within the range of −20 to 100°C. This reaction may be caused to continue until the addition of thediarylalkene type compound completes while the situation of the advanceof the reaction is checked by quantitative analysis of a samplecollected from the reaction system by an analysis method such as gaschromatography or a nuclear magnetic resonance absorption spectrum(NMR). Usually, the time necessary for the reaction is within the rangeof 1 minute to 72 hours.

[0095] In the case that a (meth)acrylic ester is add to thepolymerization system containing the polymerization initiator compoundprepared as above and is then polymerized in the polymerization process(Y) according to the present invention, the addition is performed afterthe (meth)acrylic ester is mixed with an organoaluminum compound (I) toprepare a mixture. By selecting and using the organoaluminum compound(I) as an organoaluminum compound which is caused to be present in thesystem for polymerizing the (meth)acrylic ester and further the additionof the organoaluminum compound (I) in the form of a mixture with the(meth)acrylic ester to the polymerization system as well as by the useof the polymerization initiator compound comprising an addition reactionproduct of the organic alkali metal compound and the diarylalkene typecompound, the following advantages of the present invention can beattained in the polymerization process (Y) according to the presentinvention: enlargement of the scope of the (meth)acrylic ester, theorganic alkali metal compound and the solvent media for polymerizationthat can be used; making cooling conditions mild upon thepolymerization; and an improvement in polymerization results (initiationefficiency and living polymerization property).

[0096] As the organoaluminum compound (I), a preferred compound isappropriately selected and used, dependently on the kinds of themonomers, for example, the (meth)acrylic ester to be used, and the like.The above-mentioned organoaluminum compound (I-2) or (I-3) is morepreferred in view of high polymerization rate, high initiationefficiency, high living polymerization property, a mild coolingcondition upon the polymerization, and the like. Concerning theorganoaluminum compound (I) [including the organoaluminum compounds(I-1), (I-2) and (I-3), which are subordinate concept thereof, and theorganoaluminum compounds represented by the general formulae (A) and(B)], the explanation except the above-mentioned points overlaps withthe explanation for the polymerization process (X).

[0097] The polymerization process (Y) according to the present inventiongenerally comprises an operation of addition reaction of a diarylalkenetype compound with an organic alkali metal compound to prepare apolymerization initiator compound, an operation of mixing of a (meth)acrylic ester and an organoaluminum compound (I) to prepare a mixture ofthe two, and an operation of addition of the mixture to thepolymerization system containing the polymerization initiator compoundto polymerize the (meth)acrylic ester.

[0098] The mixture of the (meth)acrylic ester and the organoaluminumcompound (I) can be prepared by mixing the two. It can be presumed thatin the polymerization process (Y), the organoaluminum compound (I) iscoordinated to the carbonyl group of the (meth)acrylic ester by thismixing so that a side reaction which can be caused when the(meth)acrylic ester is added without accompanying the organoaluminumcompound (I) to the polymerization system (nucleophilic attack againstthe carbonyl group of the (meth)acrylic ester) can be suppressed. Fromthe standpoint of easy exhibition of the advantages of the presentinvention, the (meth)acrylic ester used to prepare the mixture with theorganoaluminum compound (I) preferably corresponds to the substantiallytotal amount of the (meth)acrylic ester to be added to thepolymerization system containing the polymerization initiator compoundprepared by addition-reaction of the diarylalkene type compound with theorganic alkali metal compound. The present invention is not limited tosuch a case so far as the advantages of the present invention areexhibited. For example, it is allowable that 50% or more by mole of the(meth)acrylic ester to be added to the polymerization system containinga polymerization initiator compound is added in the form of a mixturewith the organoaluminum compound (I) to the polymerization system, andthe remainder of the (meth)acrylic ester [less than 50% by mole of the(meth)acrylic ester to be added] is added, without being mixed with theorganoaluminum compound (I). From the standpoint of easy exhibition ofthe advantages of the present invention, the amount of theorganoaluminum compound (I) used to prepare a mixture with the(meth)acrylic ester is preferably 0.01 mole or more per mole of the(meth)acrylic ester used to prepare the mixture. The upper limit of therange of a preferred amount of the organoaluminum compound (I) used toprepare the mixture with the (meth)acrylic ester is not strictlylimited. In general, however, the amount is 300 moles or less per moleof the above-mentioned polymerization initiator compound. The mixing ofthe (meth)acrylic ester and the organoaluminum compound (I) may beconducted in an organic solvent so far as an adverse effect onsubsequent polymerization is not produced. Examples of the organicsolvent that can be used include n-hexane, n-heptane, cyclohexane,methylcyclohexane, benzene, toluene, diethyl ether and1,2-dimethoxyethane. The amount of the organic solvent is not limitedand can be selected at will. Usually, the amount is 100 parts or less byweight per part of the organoaluminum compound. It is desired that themixing of the (meth)acrylic ester and the organoaluminum compound (I) isconducted in the system containing water content as less as possible, inorder to avoid incorporation of water content into the system on thesubsequent polymerization. Therefore, it is preferred that as chemicalsubstances that are supplied to the system, such as the (meth)acrylicester, the organoaluminum compound (I) and any other chemical substance(for example, the organic solvent), substances that contains watercontent as less as possible are used. If necessary, therefore, they maybe subjected to deaeration or dehydration treatment. The mixing ispreferably conducted under the atmosphere of an inert gas such asnitrogen, argon or helium.

[0099] Furthermore, if necessary, stirring may be conducted in thepreparation of the mixture of the (meth)acrylic ester and theorganoaluminum compound (I) in order that they contact each othersufficiently.

[0100] The temperature upon the mixing of the (meth)acrylic ester andthe organoaluminum compound (I) in the polymerization process (Y)according to the present invention is not particularly limited. In manycases, a temperature within the range of −50 to 100° C. can be adopted.The time necessary for the mixing is not particularly limited. In normalcases, the time is within the range of 10 seconds to 24 hours since itis sufficient that the (meth)acrylic ester and the organoaluminumcompound (I) contact each other.

[0101] If the polymerization initiator compound is brought into contactwith the organoaluminum compound (I) alone before being brought intocontact with the mixture of the organoaluminum compound (I) and the(meth)acrylic ester in the polymerization process (Y) according to thepresent invention, the polymerization initiator efficiency of the(meth)acrylic ester trends to drop. Therefore, it is preferred to avoidaddition of the organoaluminum compound (I) alone to the polymerizationsystem containing the polymerization initiator compound before additionof the mixture of the organoaluminum compound (I) and the (meth)acrylicester to the polymerization system.

[0102] In the polymerization reaction in the polymerization process (Y)according to the present invention, the following additive may be causedto be present in the polymerization system if desired: an ethercompound; a tertiary polyamine compound; an inorganic salt such aslithium chloride; a metal alkoxide compound such as lithiummethoxyethoxyethoxide or potassium tert-butoxide; or an organicquaternary salt such as tetraethylammonium chloride ortetraethylphosphonium bromide. In the case that the above-mentionedether compound or the above-mentioned tertiary polyamine compound iscaused to be present, it is possible to improve initiation efficiency(or block efficiency) and polymerization rate still more and furtherimprove living polymerization property still more by suppressinginactivation in the polymerization of the (meth)acrylic ester. Thus,this case is preferred. The explanation on the ether compound and thetertiary polyamine compound which can be used in the polymerizationprocess (Y) and conditions for using them overlaps with theabove-mentioned explanation for the polymerization process (X).

[0103] In the polymerization reaction in the polymerization process (Y)according to the present invention, any polymerization manner, forexample, solution polymerization, bulk polymerization or precipitationpolymerization, can be adopted. Since the temperature of thepolymerization can be controlled and conditions can be made uniform inthe polymerization system to advance the polymerization smoothly, it ispreferred to adopt solution polymerization in an organic solvent. Theorganic solvent is not necessarily limited. There is preferably used anaromatic hydrocarbon solvent such as benzene, toluene, ethylbenzene orxylene; a saturated hydrocarbon solvent such as hexane, cyclohexane, ormethylcyclohexane; a halogenated hydrocarbon solvent such as chloroform,methylene chloride or carbon tetrachloride; an ester solvent such asdimethyl phthalate; or the like in view of relatively high safety onhandling thereof, less incorporation into waste liquid, and easyrecovery and purification thereof. These organic solvents may be usedalone or in combination of two or more.

[0104] In the case that the organic solvent is used, the amount thereofmay be appropriately adjusted, dependently on the polymerization degreeof a target polymer, the kinds of the monomers, for example, the(meth)acrylic ester, the kind of the polymerization initiator compound,the kind of the organoaluminum compound (I), the kind of the organicsolvent, and the like. In general, the organic solvent is used in anamount of 200 to 3000 parts by weight per 100 parts by weight of thetotal of the polymerization initiator compound and the monomers from thestandpoint of smooth advance of the polymerization, easy separation ofthe resultant polymer and reduction in a burden of disposal of wastefluid.

[0105] In the polymerization reaction in the polymerization process (Y)according to the present invention, it is desired that incorporation ofwater content into the polymerization reaction system is avoided as muchas possible. Therefore, it is preferred that as chemical substances thatare supplied to the system, such as the monomers, the organoaluminumcompound (I) and any other chemical substances (for example, the organicsolvent, the ether compound, and the tertiary polyamine compound),substances that contains water content as less as possible are used. Ifnecessary, therefore, they may be subjected to deaeration or dehydrationtreatment. The polymerization reaction is preferably conducted under theatmosphere of an inert gas such as nitrogen, argon or helium.

[0106] Furthermore, in order to make reaction conditions uniform in thepolymerization reaction system, for example, the polymerization ispreferably conducted with vigorous stirring. In the case that thepolymerization reaction of a (meth)acrylic ester is conducted in thepresence of the ether compound or the tertiary polyamine compound, thetiming of adding this compound is not necessarily limited. It ispreferred to adopt such a manner that this compound can contact theorganoaluminum compound (I) before contacting a polymerization initiatorcompound.

[0107] The following will describe polymerization reaction common to thepolymerization processes (X) and (Y) according to the present invention.

[0108] In the polymerization processes (X) and (Y) according to thepresent invention, the temperature in the polymerization system is notparticularly limited. A preferred temperature is appropriately selectedand adopted, dependently on the kinds of the monomers, for example, the(meth)acrylic ester to be polymerized, and the like. In many cases, atemperature within the range of −60 to 100° C. is preferably adopted,and a temperature within the range of −50 to 50° C. is more preferablyadopted. For example, in the case that a methacrylic ester ispolymerized, a temperature within the range of −40 to 100° C. ispreferably adopted, and a temperature within the range of −30 to 50° C.is more preferably adopted. In the case that an acrylic ester ispolymerized, a temperature within the range of −60 to 50° C. ispreferably adopted, and a temperature within the range of −50 to 30° C.is more preferably adopted. The polymerization processes (X) and (Y)according to the present invention can make the condition for coolingthe polymerization system milder than conventional anionicpolymerization. Even if the polymerization is conducted at a temperaturenearer to room temperature, high living polymerization property can beattained.

[0109] In the polymerization reaction of a (meth)acrylic ester in thepolymerization processes (X) and (Y) according to the present invention,the reaction is appropriately caused to continue by quantitativelyanalyzing a sample collected from the polymerization reaction system byan analysis method such as gas chromatography, gel permeationchromatography (GPC) or a nuclear magnetic resonance absorption spectrum(NMR) and then checking the situation of the advance of thepolymerization. Usually, the time necessary for the reaction is withinthe range of 1 minute to 24 hours.

[0110] In the polymerization processes (X) and (Y) according to thepresent invention, the rate of the polymerization reaction can be madehigher by conducting the polymerization reaction of a (meth)acrylicester in the presence of the above-mentioned ether compound or tertiarypolyamine compound. That is, in the case of a methacrylic ester, thepolymerization thereof can be completed within several minutes. In thecase of an acrylic ester, the polymerization thereof can be completedwithin several tens of seconds. Accordingly, in the case that thepolymerization reaction according to the present invention is conductedin the presence of the ether compound or tertiary polyamine compound, a“continuous tube reactor polymerization” process, wherein productivityis high and cooling efficiency is good, can be adopted.

[0111] In the polymerization processes (X) and (Y) according to thepresent invention, the polymerization reaction can be terminated byaddition of a polymerization terminator, according to known anionicpolymerization, at the stage in which a target polymer chain has beenproduced. As the polymerization terminator, for example, a proticcompound such as methanol, acetic acid, or hydrochloric acid in methanolcan be used. The amount of the polymerization terminator is notparticularly limited. In general, the amount is preferably within therange of 1 to 100 moles per mole of the alkali metal atom (or anioniccenter) of the polymerization initiator compound.

[0112] In the polymerization processes (X) and (Y) according to thepresent invention, a terminal functional group supplying agent (forexample, aldehyde, lactone or carbon dioxide) may be added to thereaction system after complete end of given polymerization and beforethe addition of the polymerization terminator. In this case, it ispossible to obtain a polymer having in the terminal of its molecularchain a functional group such as a hydroxyl group or a carboxyl group. Amultifunctional compound having in the molecule thereof two or morefunctional groups such as a formyl, keto, chlorocarbonyl or halogenatedsilyl group may also be added to the reaction system after complete endof given polymerization and before the addition of the polymerizationterminator. In this case, it is possible to obtain a linear orstar-shaped polymer wherein two or more polymers are bonded (coupled) toeach other through a residue originating from the multifunctionalcompound as a center.

[0113] If a metal component originating from the used polymerizationinitiator compound or the used organoaluminum compound (I) remains inthe polymer obtained by separation from the reaction mixture after thetermination of the polymerization, physical properties of the polymer ora material containing it may drop or transparency thereof maydeteriorate. Therefore, the metal component originating from thepolymerization initiator compound or the organoaluminum compound (I) ispreferably removed, dependently on the purpose of the use of thepolymer, after the termination of the polymerization. As the method forremoving such a metal component, a method comprising subjecting thepolymer to cleaning treatment, such as washing treatment with an acidicaqueous solution or adsorbing treatment with an adsorbent such as an ionexchange resin, is effective. As the acidic aqueous solution, there maybe used, for example, hydrochloric acid, aqueous sulfuric acid solution,aqueous nitric acid solution, aqueous acetic acid solution, aqueouspropionic acid solution, aqueous citric acid solution, or the like.

[0114] The method for separating the polymer from the reaction mixtureafter the termination of the polymerization is not particularly limited.A method according to any one of known methods can be adopted. Forexample, there may be adopted a method comprising pouring the reactionmixture into a poor solvent for the polymer to precipitate the polymer,or a method comprising distilling the solvent away from the reactionmixture to gain the polymer.

[0115] According to the polymerization processes (X) and (Y) of thepresent invention, a polymer having any molecular weight can beproduced. The molecular weight of the polymer that can be producedextends over a wide range. In general, the number average molecularweight thereof is preferably within the range of 1000 to 1000000 in viewof handling performance, fluidity and mechanical properties of theresultant polymer. According to the polymerization processes (X) and (Y)of the present invention, a polymer having a highly uniform molecularweight (that is, a narrow molecular weight distribution) can be usuallyobtained. A polymer having a molecular weight distribution value (Mw/Mn)of 1.5 or less can be produced. However, a polymer having a widemolecular weight distribution can be intentionally produced bycontrolling the addition speed of the monomers to the polymerizationsystem, the diffusion rate of the monomers into the polymerizationsystem, or the like.

[0116] The present invention will be more specifically described by wayof working examples. However, the present invention is not limited tothe following working examples. Examples 1-10 described below areexperimental examples according to the polymerization process (X) of thepresent invention, and Examples 11-15 described below are experimentalexamples according to the polymerization process (Y) of the presentinvention.

[0117] In the examples and the like described below, chemical substanceswere dried and purified according to a usual way, and were thendeaerated with nitrogen. The thus obtained chemical substances wereused. Transportation and supply of the chemical substances wereperformed under the atmosphere of nitrogen.

EXAMPLE 1 Synthesis Example of a Styrene/Tert-Butyl Methacrylate BlockCopolymer

[0118] The present example is a production example of astyrene/tert-butyl methacrylate block copolymer, comprising the step ofpreparing polystyryllithium (an organic alkali metal compound) byanionic polymerization of styrene, the step of preparing apolymerization initiator compound by addition reaction of butadiene, andthe step of polymerizing tert-butyl methacrylate in the presence ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum (an organoaluminumcompound). Using the fact that any styrene polymer has a property of UVabsorption and any tert-butyl methacrylate polymer does not have aproperty of UV absorption, the block efficiency in the blockcopolymerization (the initiation efficiency in the polymerization oftert-butyl methacrylate) was obtained.

[0119] (1) A magnetic stirrer chip was put into a 50 ml Schlenk tubewith a three-way cock, and then the inside thereof was replaced bynitrogen. Thereto were added 25 ml of cyclohexane and 1.0 ml of acyclohexane solution containing 0.13 mmol of sec-butyllithium. To thissolution was added 2.0 g of styrene, and then the resultant solution wasstirred at 40° C. for 3 hours to prepare a solution containingpolystyryllithium.

[0120] (2) To the solution in the Schlenk tube, which was obtained inthe above-mentioned step (1), was added 0.20 ml of a cyclohexanesolution containing 0.30 mmol of butadiene at 40° C. Immediately, thecolor of solution was changed from orange color to colorlessness.Stirring was continued at the same temperature for 10 minutes.

[0121] About 0.5 ml of a sample was collected from the resultantreaction mixture solution, and subjected to gas chromatography(hereinafter referred to as “GC”). As a result, it was proved that theconversion of butadiene and styrene was 99% or more. Analysis of GPC(reduced to polystyrene) proved that the peak top molecular weight ofthe resultant addition reaction product of polystyryllithium andbutadiene was 17100, the number average molecular weight thereof was16400, and the ratio of the weight average molecular weight to thenumber average molecular weight (Mw/Mn) was 1.03.

[0122] (3) The solution in the Schlenk tube, which was obtained in thestep (2), was cooled to 15° C., and then 0.81 ml of a toluene solutioncontaining 0.65 mmol ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum was added thereto.The resultant solution was stirred for 10 minutes.

[0123] Next, while the resultant solution was vigorously stirred, 1.0 gof tert-butyl methacrylate was added thereto. Polymerization wasconducted at 15° C. for 5 hours with stirring. Thereafter, about 0.05 mlof methanol was added thereto, so as to terminate the polymerization.

[0124] A part of the resultant reaction mixture solution was sampled andwas analyzed by GC. As a result, it was proved that the conversion oftert-butyl methacrylate was 100%.

[0125] The solvent was removed from the resultant reaction mixturesolution by vacuum drying, to obtain a polymer. GPC-W (254 nm)measurement (reduced to polystyrene) proved that the resultant polymerwas a mixture of a block copolymer (Mt=29100) and a polymer originatingfrom the polymerization initiator compound (Mt=18000; polystyrene havinga butadiene fragment at its terminal) and the weight ratio of the formerto the latter was 73/27.

[0126] This demonstrated that the block efficiency of the blockcopolymerization was 73%.

COMPARATIVE EXAMPLE 1

[0127] Preparation of polystyryllithium by anionic polymerization ofstyrene, preparation of a polymerization initiator compound by additionreaction of butadiene, and polymerization of tert-butyl methacrylate inthe presence of an organoaluminum compound were successively performedin the same way as in Example 1 except that instead ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum, triethylaluminumof the mole equivalent thereto was used as the organoaluminum compound.

[0128] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound proved that Mt was 16900, Mn was 16200and Mw/Mn was 1.03.

[0129] After the step of polymerization of tert-butyl methacrylate, theresultant reaction mixture solution was analyzed by GC. As a result, itwas proved that the conversion of tert-butyl methacrylate was about100%.

[0130] GPC-UV (254 nm) measurement (reduced to polystyrene) proved thatthe polymer obtained after the solvent was removed was a mixture of ahigher molecular weight component (Mt=34100 and Mn=35700) and a polymeroriginating from the polymerization initiator compound (Mt=17400 andMn=16600; polystyrene having a butadiene fragment at its terminal) andthe weight ratio of the former to the latter was 63/37. From the factthat about the area ratio of the peak of the higher molecular weightcomponent, the result measured with a GPC-UV detector was substantiallyequal to the result measured with a GPC-RI detector, and the fact thatthe Mt of the higher molecular weight component was about two times Mtof the polymer originating from the polymerization initiator compound,it was presumed that the main of the higher molecular weight componentwas a dimer of the polymerization initiator compound (a coupled productobtained by nucleophilically adding two molecules of the polymerizationinitiator compound anion to the carbonyl group of one molecule oftert-butyl methacrylate). This fact demonstrated that the main componentof the resultant polymer was polystyrenes containing butadiene fragment.

COMPARATIVE EXAMPLE 2

[0131] Preparation of polystyryllithium by anionic polymerization ofstyrene, preparation of a polymerization initiator compound by additionreaction of butadiene, and polymerization of tert-butyl methacrylate inthe presence of an organoaluminum compound were successively performedin the same way as in Example 1 except that instead ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum,triisobutylaluminum of the mole equivalent thereto was used as theorganoaluminum compound.

[0132] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound proved that Mt was 17400, Mn was 16800and Mw/Mn was 1.03.

[0133] After the step of polymerization of tert-butyl methacrylate, theresultant reaction mixture solution was analyzed by GC. As a result, itwas proved that the conversion of tert-butyl methacrylate was about100%.

[0134] GPC-UV (254 nm) measurement (reduced to polystyrene) proved thatthe polymer obtained after the solvent was removed was a mixture of ahigher molecular weight component (Mt=34800 and Mn=37300) and a polymeroriginating from the polymerization initiator compound (Mt=18200 andMn=17500; polystyrene having a butadiene fragment at its terminal) andthe weight ratio of the former to the latter was 51/49. From the factthat about the area ratio of the peak of the higher molecular weightcomponent, the result measured with a GPC-UV detector was substantiallyequal to the result measured with a GPC-RI detector, and the fact thatthe Mt of the higher molecular weight component was about two times Mtof the polymer originating from the polymerization initiator compound,it was presumed that the main of the higher molecular weight componentwas a dimer of the polymerization initiator compound (a coupled productobtained by nucleophilically adding two molecules of the polymerizationinitiator compound anion to the carbonyl group of one molecule oftert-butyl methacrylate). This fact demonstrated that the main componentof the resultant polymer was polystyrenes containing butadiene fragment.

[0135] The following can be understood from results of the Example 1 andresults of Comparative Examples 1 and 2: in the case that inpolymerization of a methacrylic ester in the presence of anorganoaluminum compound using a polymerization initiator compoundcomprising an addition reaction product of an organic alkali metalcompound and a conjugated diene compound, the above-mentioned specificorganoaluminum compound (I) is used as the organoaluminum compound(Example 1), polymerization with a high initiation efficiency (blockefficiency) can be achieved even under such polymerization conditionsthat any polymerization does not advance in the case thattrialkylaluminum, which is common as the organoaluminum compound, isused (Comparative Examples 1 and 2).

EXAMPLE 2 Synthesis Example of a Styrene/Methyl Methacrylate BlockCopolymer

[0136] The present example is a production example of a styrene/methylmethacrylate block copolymer, comprising the step of preparingpolystyryllithium (an organic alkali metal compound) by anionicpolymerization of styrene, the step of preparing a polymerizationinitiator compound by addition reaction of butadiene, and the step ofpolymerizing methyl methacrylate in the presence ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum (an organoaluminumcompound).

[0137] (1) A magnetic stirrer chip was put into a 50 ml Schlenk tubewith a three-way cock, and then the inside thereof was replaced bynitrogen. Thereto were added 25 ml of toluene and 0.12 ml of acyclohexane solution containing 0.15 mmol of sec-butyllithium. To thissolution was added 0.75 g of styrene, and then the resultant solutionwas stirred at 23° C. for 1.5 hours to prepare a solution containingpolystyryllithium.

[0138] (2) To the solution in the Schlenk tube, which was obtained inthe above-mentioned step (1), was added 0.40 ml of a cyclohexanesolution containing 0.60 mmol of butadiene at 23° C. Immediately, thecolor of solution was changed from orange color to colorlessness.Stirring was continued at the same temperature for 10 minutes.

[0139] A part of the resultant reaction mixture solution was sampled,and subjected to GC analysis. As a result, it was proved that theconversion of butadiene and styrene was 99% or more. Analysis of GPC(reduced to polystyrene) proved that Mn of the resultant additionreaction product of polystyryllithium and butadiene was 5700 and Mw/Mnwas 1.03.

[0140] (3) The solution in the Schlenk tube, which was obtained in thestep (2), was cooled to −30° C., and then 1.0 ml of a toluene solutioncontaining 0.80 mmol ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum was added thereto.The resultant solution was stirred for 10 minutes.

[0141] Next, while the resultant solution was vigorously stirred, 2.25 gof methyl methacrylate was added thereto. Polymerization was conductedat −30° C. for 2 hours with stirring. Thereafter, about 0.05 ml ofmethanol was added thereto, so as to terminate the polymerization.

[0142] The resultant reaction mixture solution was subjected to aprecipitation treatment with 300 ml of methanol, to obtain a polymer.The yield of the resultant polymer was about 100%. GPC-UV (254 nm)measurement (reduced to polystyrene) proved that the resultant polymerwas a mixture of a block copolymer (Mn=23300 and Mw/Mn=1.05) and apolymer originating from the polymerization initiator compound(polystyrene having a butadiene fragment at its terminal) and the weightratio of the former to the latter was 96/4. This demonstrated that theblock efficiency of the block copolymerization was 96%.

[0143] The used chemical substances, adopted polymerization conditionsand results are shown in Table 1 described below.

EXAMPLE 3 Synthesis Example of Styrene/Methyl Methacrylate BlockCopolymer

[0144] Preparation of polystyryllithium by anionic polymerization ofstyrene, preparation of a polymerization initiator compound by additionreaction of butadiene, and polymerization of methyl methacrylate in thepresence of an organoaluminum compound were successively performed inthe same way as in Example 2 except that the temperature whendiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum was added, thetemperature when methyl methacrylate was added, and polymerizationtemperature were changed from −30° C. to 0° C. and the time forpolymerization of methyl methacrylate was changed from 2 hours to 1hour.

[0145] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound proved that Mn was 5200 and Mw/Mn was1.03.

[0146] After the step of polymerizing methyl methacrylate, the resultantreaction mixture solution was subjected to a precipitation treatment toobtain a polymer. The yield of the resultant polymer was about 100%.GPC-UV (254 nm) measurement (reduced to polystyrene) proved that theresultant polymer was a mixture of a block copolymer (Mn=23600 andMw/Mn=1.06), a dimer of the polymerization initiator compound (acompound presumed as a coupled product obtained by nucleophilicallyadding two molecules of the polymerization initiator compound anion tothe carbonyl group of one molecule of methyl methacrylate) and a polymeroriginating from the polymerization initiator compound (polystyrenehaving a butadiene fragment at its terminal), and the weight ratio amongthem was 85/6/9. This demonstrated that the block efficiency of theblock copolymerization was 85%.

[0147] The used chemical substances, adopted polymerization conditionsand results are shown in Table 1 described below.

EXAMPLE 4 Synthesis Example of Styrene/Methyl Methacrylate BlockCopolymer

[0148] Preparation of polystyryllithium by anionic polymerization ofstyrene, preparation of a polymerization initiator compound by additionreaction of a conjugated diene compound, and polymerization of methylmethacrylate in the presence of an organoaluminum compound weresuccessively performed in the same way as in Example 2 except thatinstead of butadiene, isoprene of the mole equivalent thereto was usedas the conjugated diene compound.

[0149] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound proved that Mn was 5300 and Mw/Mn was1.04.

[0150] After the step of polymerizing methyl methacrylate, the resultantreaction mixture solution was subjected to a precipitation treatment toobtain a polymer. The yield of the resultant polymer was about 100%.GPC-UV (254 nm) measurement (reduced to polystyrene) proved that theresultant polymer was a mixture of a block copolymer (Mn=24500 andMw/Mn=1.07), a dimer of the polymerization initiator compound (acompound presumed as a coupled product obtained by nucleophilicallyadding two molecules of the polymerization initiator compound anion tothe carbonyl group of one molecule of methyl methacrylate) and a polymeroriginating from the polymerization initiator compound (polystyrenehaving a isoprene fragment at its terminal), and the weight ratio amongthem was 80/8/12. This demonstrated that the block efficiency of theblock copolymerization was 80%.

[0151] The used chemical substances, adopted polymerization conditionsand results are shown in Table 1 described below.

EXAMPLE 5 Synthesis Example of Styrene/Methyl Methacrylate BlockCopolymer

[0152] Preparation of polystyryllithium by anionic polymerization ofstyrene, preparation of a polymerization initiator compound by additionreaction of butadiene, and polymerization of methyl methacrylate in thepresence of an organoaluminum compound were successively performed inthe same way as in Example 3 except that a solution prepared by mixing1.0 ml of a toluene solution containing 0.80 mmol ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum with 0.22 g of1,2-dimethoxyethane was used instead of 1.0 ml of the toluene solutioncontaining 0.80 mmol ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum.

[0153] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound proved that Mn was 5500 and Mw/Mn was1.03.

[0154] After the step of polymerizing methyl methacrylate, the resultantreaction mixture solution was subjected to a precipitation treatment toobtain a polymer. The yield of the resultant polymer was about 100%.GPC-UV (254 nm) measurement (reduced to polystyrene) proved that theresultant polymer was a mixture of a block copolymer (Mn=23800 andMw/Mn=1.06) and a polymer originating from the polymerization initiatorcompound (polystyrene having a butadiene fragment at its terminal) andthe weight ratio of the former to the latter was 93/7. This demonstratedthat the block efficiency of the block-copolymerization was 93%.

[0155] The used chemical substances, adopted polymerization conditionsand results are shown in Table 1 described below.

COMPARATIVE EXAMPLE 3

[0156] Preparation of polystyryllithium by anionic polymerization ofstyrene, preparation of a polymerization initiator compound by additionreaction of butadiene, and polymerization of methyl methacrylate in thepresence of an organoaluminum compound were successively performed inthe same way as in Example 2 except that instead ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum, triethylaluminumof the mole equivalent thereto was used as the organoaluminum compoundand the time for polymerizing methyl methacrylate was extended from 2hours to 24 hours.

[0157] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound proved that Mn was 5600 and Mw/Mn was1.03.

[0158] After the step of polymerizing methyl methacrylate, the resultantreaction mixture solution was subjected to a precipitation treatment toobtain a polymer. The yield of the resultant polymer was about 100%.GPC-UV (254 nm) measurement (reduced to polystyrene) proved that theresultant polymer was a mixture of a block copolymer (Mn=49800 andMw/Mn=1.14), a dimer of the polymerization initiator compound (acompound presumed as a coupled product obtained by nucleophilicallyadding two molecules of the polymerization initiator compound anion tothe carbonyl group of one molecule of methyl methacrylate) and a polymeroriginating from the polymerization initiator compound (polystyrenehaving a butadiene fragment at its terminal) and the weight ratio amongthem was 37/42/21. This demonstrated that the block efficiency of theblock copolymerization was 37%.

[0159] The used chemical substances, adopted polymerization conditionsand results are shown in Table 1 described below.

COMPARATIVE EXAMPLE 4

[0160] Preparation of polystyryllithium by anionic polymerization ofstyrene, preparation of a polymerization initiator compound by additionreaction of butadiene, and polymerization of methyl methacrylate in thepresence of an organoaluminum compound were successively performed inthe same way as in Comparative Example 3 except that instead oftriethylaluminum, triisobutylaluminum of the mole equivalent thereto wasused as the organoaluminum compound.

[0161] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound proved that Mn was 5100 and Mw/Mn was1.04.

[0162] After the step of polymerizing methyl methacrylate, the resultantreaction mixture solution was subjected to a precipitation treatment toobtain a polymer. The yield of the resultant polymer was about 100%.GPC-UV (254 nm) measurement (reduced to polystyrene) proved that theresultant polymer was a mixture of a block copolymer (Mn=41900 andMw/Mn=1.12), a dimer of the polymerization initiator compound (acompound presumed as a coupled product obtained by nucleophilicallyadding two molecules of the polymerization initiator compound anion tothe carbonyl group of one molecule of methyl methacrylate) and a polymeroriginating from the polymerization initiator compound (polystyrenehaving a butadiene fragment at its terminal) and the weight ratio amongthem was 41/35/24. This demonstrated that the block efficiency of theblock copolymerization was 41%.

[0163] The used chemical substances, adopted polymerization conditionsand results are shown in Table 1 described below.

COMPARATIVE EXAMPLE 5

[0164] Preparation of polystyryllithium by anionic polymerization ofstyrene and polymerization of methyl methacrylate in the presence of anorganoaluminum compound were successively performed in the same way asin Example 2 except that polystyryllithium was used as thepolymerization initiator compound for methyl methacrylate without beingsubjected to addition reaction using butadiene and the time forpolymerizing methyl methacrylate was extended from 2 hours to 3 hours.When diisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum was added tothe solution containing polystyryllithium, which was prepared by anionicpolymerization of styrene, the color of the solution, which was orangecolor originating from the growing terminal anion of polystyrene, waslost and turned colorless. This change in the color of the solutiondemonstrated that the added organoaluminum compound formed an atecomplex with the growing terminal anion of polystyrene.

[0165] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound (polystyryllithium) proved that Mn was5100 and Mw/Mn was 1.04.

[0166] After the step of polymerizing methyl methacrylate, the resultantreaction mixture solution was subjected to a precipitation treatment toobtain a polymer. ¹H-NMR analysis proved that the conversion of methylmethacrylate was about 6% and methyl methacrylate was hardlypolymerized. GPC-UV (254 nm) measurement (reduced to polystyrene) alsoproved that the resultant polymer was a polymer originating from thepolymerization initiator compound (polystyrene).

[0167] The used chemical substances, adopted polymerization conditionsand results are shown in Table 1 described below.

COMPARATIVE EXAMPLE 6

[0168] Preparation of polystyryllithium by anionic polymerization ofstyrene, preparation of a polymerization initiator compound by additionreaction of 1,1-diphenylethylene and polymerization of methylmethacrylate in the presence of an organoaluminum compound weresuccessively performed in the same way as in Example 2 except that thestep of preparation of the polymerization initiator compound by additionreaction of butadiene was changed to the step of preparation of thepolymerization initiator compound comprising addition of 0.60 ml of acyclohexane solution containing 0.60 mmol of 1,1-diphenylethylene to asolution containing polystyryllithium, which was prepared by anionicpolymerization of styrene, and reaction at 50° C. for 6 hours and thatthe time for polymerizing methyl methacrylate was extended from 2 hoursto 3 hours. The color of the solution containing polystyryllithium,which was orange, changed to dark red color after the addition of1,1-diphenylethylene. This phenomenon suggests that the terminal ofpolystyrene was capped with 1,1-diphenylethylene so that its terminalanion changed to 1, 1-diphenylmethylene anion. The color of the solutioncontaining the polymerization initiator compound, which was dark redcolor originating from the 1,1-diphenylmethylene anion, changed toorange color after the addition ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum. This phenomenonsuggests that the added organoaluminum compound formed an ate complexwith the 1,1-diphenylmethylene anion.

[0169] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound proved that Mn was 5600 and Mw/Mn was1.03.

[0170] After the step of polymerizing methyl methacrylate, the resultantreaction mixture solution was subjected to a precipitation treatment toobtain a polymer. The yield of the resultant polymer was about 100%.GPC-UV (254 nm) measurement (reduced to polystyrene) proved that theresultant polymer was a mixture of a block copolymer (Mn=38800 andMw/Mn=1.07), a dimer of the polymerization initiator compound (acompound presumed as a coupled product obtained by nucleophilicallyadding two molecules of the polymerization initiator compound anion tothe carbonyl group of one molecule of methyl methacrylate) and a polymeroriginating from the polymerization initiator compound (polystyrenehaving a 1,1-diphenylethylene fragment at its terminal) and the weightratio among them was 54/9/33. This demonstrated that the blockefficiency of the block copolymerization was 54%.

[0171] The used chemical substances, adopted polymerization conditionsand results are shown in Table 1 described below.

COMPARATIVE EXAMPLE 7

[0172] Preparation of polystyryllithium by anionic polymerization ofstyrene, preparation of a polymerization initiator compound by additionreaction of α-methylstyrene and polymerization of methyl methacrylate inthe presence of an organoaluminum compound were successively performedin the same way as in Example 2 except that the step of preparation ofthe polymerization initiator compound by addition reaction of butadienewas changed to the step of preparation of the polymerization initiatorcompound comprising addition of 1.8 mmol of α-methylstyrene to asolution containing polystyryllithium, which was prepared by anionicpolymerization of styrene, and reaction at 50° C. for 3 hours and thatthe time for polymerizing methyl methacrylate was extended from 2 hoursto 3 hours. The color of the solution containing polystyryllithium,which was orange, changed to dark red color after the addition ofα-methylstyrene. This phenomenon suggests that the terminal ofpolystyrene was capped with α-methylstyrene so that its terminal anionchanged to α-methylstyryl anion. The color of the solution containingthe polymerization initiator compound, which was dark red colororiginating from the α-methylstyryl anion, changed to orange color afterthe addition of diisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum.This phenomenon suggests that the added organoaluminum compound formedan ate complex with the a-methylstyryl anion.

[0173] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound proved that Mn was 6100 and Mw/Mn was1.04.

[0174] After the step of polymerizing methyl methacrylate, the resultantreaction mixture solution was subjected to a precipitation treatment toobtain a polymer. ¹H-NMR analysis proved that the conversion of methylmethacrylate was about 3% and methyl methacrylate was hardlypolymerized. GPC-UV (254 nm) measurement (reduced to polystyrene) alsoproved that the resultant polymer was a polymer originating from thepolymerization initiator compound (polystyrene).

[0175] The used chemical substances, adopted polymerization conditionsand results are shown in Table 1 described below. TABLE 1 Polymerizationconditions Polymerization results Unsaturated Organo- PolymerizationConversion Block Block compound for Initiator aluminum temperature timeof monomer copolymer efficiency an initiator Mn compound Additive (° C.)(hour) (%) Mn Mw/Mn (%) Example 2 1,3- 5700 iB₂Al(BHT) — −30 2 100 233001.05 96 butadiene Example 3 1,3- 5200 iB₂Al(BHT) — 0 1 100 23600 1.06 85butadiene Example 4 isoprene 5300 iB₂Al(BHT) — −30 2 100 24500 1.07 80Example 5 1,3- 5500 iBAl(BHT)₂ DME 0 1 100 23800 1.06 93 butadieneComparative 1,3- 5600 ET₃Al — −30 24 100 49800 1.14 37 Example 3butadiene Comparative 1,3- 5100 iB₃Al — −30 24 100 41900 1.12 41 Example4 butadiene Comparative none 5100 iB₂Al(BHT) — −30 3 about 6 — — —Example 5 Comparative 1,1- 5600 iB₂Al(BHT) — −30 3 100 38800 1.07 54Example 6 diphenyl- ethylene Comparative α-methyl- 6100 iB₂Al(BHT) — −303 about 3 — — — Example 7 styrene

[0176] In the above-mentioned Table 1, symbols in the columns of“organoaluminum compound” and “additive” mean the following compounds.

[0177] iB₂Al(BHT): diisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum

[0178] iBAl(BHT)₂: isobutylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum

[0179] Et₃Al: triethylaluminum

[0180] iB₃Al: triisobutylaluminum

[0181] DME: 1,2-dimethoxyethane

[0182] The following can be understood from results of the Examples 2-5:in the case that in polymerization of a methacrylic ester in thepresence of an organoaluminum compound using an anionic polymerizationinitiator compound, an addition reaction product of an organic alkalimetal compound such as polystyryllithium and a conjugated diene compoundis used as the anionic polymerization initiator compound and theabove-mentioned specific organoaluminum compound (I) is used as theorganoaluminum compound, a high initiation efficiency (block efficiency)can be attained. On the other hand, it can be understood from results ofComparative Examples 3-7 that when trialkylaluminum, which is a commonorganoaluminum compound, is used as the organoaluminum compound(Comparative Examples 3 and 4), the initiation efficiency (blockefficiency) becomes low and when an organic alkali metal compound suchas polystyryllithium is used as it is or in the form of an additionreaction product with an unsaturated compound other than conjugateddiene compounds, as the anionic polymerization initiator compound(Comparative Examples 5-7), the conversion of monomer becomes very lowor the initiation efficiency (block efficiency) becomes low.

EXAMPLE 6 Synthesis Example of a Styrene/N-Butyl Acrylate BlockCopolymer

[0183] The present example is a production example of a styrene/n-butylacrylate block copolymer, comprising the step of preparingpolystyryllithium (an organic alkali metal compound) by anionicpolymerization of styrene, the step of preparing a polymerizationinitiator compound by addition reaction of butadiene, and the step ofpolymerizing n-butyl acrylate in the presence ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum (anorganoaluminum compound). The block efficiency in the blockcopolymerization (the initiation efficiency in the polymerization ofn-butyl acrylate) was obtained from the ratio between the number averagemolecular weight (reduced to polystyrene) obtained by GPC measurement ofthe resultant block copolymer and the molecular weight of the blockcopolymer calculated on the basis of the used amount and yield.

[0184] Preparation of polystyryllithium by anionic polymerization ofstyrene, preparation of a polymerization initiator compound by additionreaction of butadiene and polymerization of n-butyl acrylate in thepresence of an organoaluminum compound were successively performed inthe same way as in Example 5 except that the temperature when a solutionprepared by mixing a toluene solution containingisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum with1,2-dimethoxyethane was added was changed from 0° C. to −30° C., and thestep in which 2.25 g of n-butyl acrylate was added at −30° C. and thenpolymerized at −30° C. for 5 minutes was conducted instead of the stepin which 2.25 g of methyl methacrylate was added at 0° C. and thenpolymerized at 0° C. for 1 hour.

[0185] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound proved that Mn was 5000 and Mw/Mn was1.04.

[0186] After the step of polymerizing n-butyl acrylate, the resultantreaction mixture solution was subjected to a precipitation treatment toobtain a polymer. The yield of the resultant polymer was about 100%.GPC-UV (254 nm) measurement (reduced to polystyrene) proved that theresultant polymer was a mixture of a block copolymer (Mn=21500 andMw/Mn=1.09), and a polymer originating from the polymerization initiatorcompound (polystyrene having a butadiene fragment at its terminal) andthe weight ratio of the former to the latter was 96/4.

[0187] The block efficiency was estimated as 91% on the basis of themolecular weight of the polymerization initiator compound and themolecular weight and the yield of the block copolymer.

[0188] The used chemical substances, adopted polymerization conditionsand results are shown in Table 2 described below.

Example 7 Synthesis Example of a Styrene/N-Butyl Acrylate BlockCopolymer

[0189] Preparation of polystyryllithium by anionic polymerization ofstyrene, preparation of a polymerization initiator compound by additionreaction of butadiene and polymerization of n-butyl acrylate in thepresence of an organoaluminum compound were successively performed inthe same way as in Example 6 except that 0.50 ml of a toluene solutioncontaining 0.40 mmol ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum was solely addedinstead of the solution prepared by mixing 1.0 ml of the toluenesolution containing 0.80 mmol ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy) aluminum with 0.22 g of1,2-dimethoxyethane; instead of only n-butyl acrylate, a solutionprepared by mixing n-butyl acrylate of the weight equivalent theretowith 0.50 ml of a toluene solution containing 0.40 mol ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum was added; andthe time for polymerizing n-butyl acrylate was changed from 5 minutes to30 minutes.

[0190] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound proved that Mn was 5100 and Mw/Mn was1.02.

[0191] After the step of polymerizing n-butyl acrylate, the resultantreaction mixture solution was subjected to a precipitation treatment toobtain a polymer. The yield of the resultant polymer was about 100%.GPC-UV (254 nm) measurement (reduced to polystyrene) proved that theresultant polymer was a mixture of a block copolymer (Mn=24000 andMw/Mn=1.12) and a polymer originating from the polymerization initiatorcompound (polystyrene having a butadiene fragment at its terminal) andthe weight ratio of the former to the latter was 93/7.

[0192] The block efficiency was estimated as 81% on the basis of themolecular weight of the polymerization initiator compound and themolecular weight and the yield of the block copolymer.

[0193] The used chemical substances, adopted polymerization conditionsand results are shown in Table 2 described below.

COMPARATIVE EXAMPLE 8

[0194] Preparation of polystyryllithium by anionic polymerization ofstyrene, preparation of a polymerization initiator compound by additionreaction of butadiene and polymerization of n-butyl acrylate in thepresence of an organoaluminum compound were successively performed inthe same way as in Example 6 except that instead ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum,triisobutylaluminum of the mole equivalent thereto was used and the timefor polymerizing n-butyl acrylate was changed from 5 minutes to 6 hours.

[0195] GPC analysis (reduced to polystyrene) of the resultantpolymerization initiator compound proved that Mn was 5800 and Mw/Mn was1.04.

[0196] After the step of polymerizing n-butyl acrylate, the resultantreaction mixture solution was subjected to a precipitation treatment toobtain a polymer. ¹H-NMR analysis of the resultant polymer proved thatno n-butyl acrylate was polymerized. GPC-UV (254 nm) measurement(reduced to polystyrene) proved that the resultant polymer was a polymeroriginating from the polymerization initiator compound (polystyrenehaving a butadiene fragment at its terminal).

[0197] The used chemical substances, adopted polymerization conditionsand results are shown in Table 2 described below. TABLE 2 Polymerizationconditions Polymerization results Conjugated Organo- Conversion BlockBlock diene for an Initiator, aluminum temperature Polymerization ofmonomer copolymer efficiency initiator Mn compound Additive (° C.) time(%) Mn Mw/Mn (%) Example 6 1,3- 5000 iBAl(BHT)₂ DME −30 5 minutes 10021500 1.09 91 butadiene Example 7 1,3- 5100 iBAl(BHT)₂ ^(a)) — −30 30100 24000 1.12 81 butadiene minutes Comparative 1,3- 5800 iB₃Al DME −306 hours 0 — — — Example 8 butadiene

[0198] In the above-mentioned Table 2, symbols in the columns of“organoaluminum compound” and “additive” mean the following compounds.

[0199] iBAl(BHT)₂: isobutylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum

[0200] iB₃Al: triisobutylaluminum

[0201] DME: 1,2-dimethoxyethane

[0202] a): addition in the form of a mixture with n-butyl acrylate

[0203] The following can be understood from results shown in Table 2: inthe case that in polymerization of an acrylic ester in the presence ofan organoaluminum compound using an polymerization initiator compoundcomprising an addition reaction product of an organic alkali metalcompound and a conjugated diene compound, the above-mentioned specificorganoaluminum compound (I) is used as the organoaluminum compound(Examples 6 and 7), a high initiation efficiency (block efficiency) canbe attained. However, in the case that trialkylaluminum, which is acommon organoaluminum compound, is used (Comparative Example 8),polymerization reaction does not advance.

EXAMPLE 8 Synthesis Example of a Methyl Methacrylate Polymer

[0204] The present example is a production example of a methylmethacrylate polymer comprising the step of preparingoligobutadienyllithium (a polymerization initiator compound) by addingbutadiene to sec-butyllithium in a small ratio of the former to thelatter, and the step of polymerizing methyl methacrylate in the presenceof diisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum (anorganoaluminum compound). The initiation efficiency in thepolymerization of methyl methacrylate was obtained from the ratiobetween the number average molecular weight (reduced to polystyrene)obtained by GPC measurement of the methyl methacrylate polymer and themolecular weight of the methyl methacrylate polymer calculated on thebasis of the used amount and yield.

[0205] (1) A magnetic stirrer chip was put into a 50 ml Schlenk tubewith a three-way cock, and then the inside thereof was replaced bynitrogen. Thereto was added 18.5 ml of a cyclohexane solution containing1.2 g of butadiene. To this solution was added 1.6 ml of a cyclohexanesolution of sec-butyllithium (concentration: 1.3 M), and then theresultant solution was stirred at 0° C. for 24 hours to conductreaction.

[0206] GPC measurement of the resultant reaction mixture solution provedthat an oligobutadienyllithium having a number average molecular weight(Mn), reduced to polystyrene, of 1200 and a molecular weightdistribution (Mw/Mn) of 1.18 was produced.

[0207] (2) A magnetic stirrer chip was put into a 50 ml Schlenk tubewith a three-way cock, and then the inside thereof was replaced bynitrogen. Thereto were added 15 ml of toluene and 1.5 ml portion of thecyclohexane solution of oligobutadienyllithium (concentration: 0.1 M),which was obtained in the above-mentioned step (1). This solution wascooled to −30° C., and then thereto was added 1.0 ml of a toluenesolution containing 0.80 mmol ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum. The resultantsolution was stirred for 10 minutes.

[0208] Next, 1.50 g of methyl methacrylate was added to the resultantsolution while the solution was vigorously stirred. Polymerization wasconducted with stirring at −30° C. for 2 hours. Thereafter, about 0.05ml of methanol was added thereto so as to terminate the polymerization.

[0209] The resultant reaction mixture solution was subjected to aprecipitation treatment with 300 ml of methanol to obtain a polymer. Theyield of the resultant polymer was about 100%. GPC measurement (reducedto polystyrene) proved that the resultant polymer had an Mn of 11900 andan Mw/Mn of 1.07.

[0210] It was understood from these results that the initiationefficiency in the polymerization of methyl methacrylate was 93%.

[0211] The used chemical substances, adopted polymerization conditionsand results are shown in Table 3 described below.

COMPARATIVE EXAMPLE 9

[0212] A magnetic stirrer chip was put into a 50 ml Schlenk tube with athree-way cock, and then the inside thereof was replaced by nitrogen.Thereto was added 15 ml of toluene and then the solution was cooled to−30° C. Thereto was added 0.95 ml of a cyclohexane solution oftert-butyllithium (concentration: 1.6 M). This solution was kept at −30°C., and then thereto was added 1.0 ml of a toluene solution containing0.80 mol of diisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum. Theresultant solution was stirred for 10 minutes.

[0213] Next, 1.50 g of methyl methacrylate was added to the resultantsolution while the solution was vigorously stirred. Polymerization wasconducted with stirring at −30° C. for 2 hours. Thereafter, about 0.05ml of methanol was added thereto so as to terminate the polymerization.

[0214] The resultant reaction mixture solution was subjected to aprecipitation treatment with 300 ml of methanol to obtain a polymer. Theyield of the resultant polymer was about 100%. GPC measurement (reducedto polystyrene) proved that the resultant polymer had an Mn of 13000 andan Mw/Mn of 1.11.

[0215] It was understood from these results that the initiationefficiency in the polymerization of methyl methacrylate was 77%.

[0216] The used chemical substances, adopted polymerization conditionsand results are shown in Table 3 described below.

COMPARATIVE EXAMPLE 10

[0217] Polymerization of methyl methacrylate in the presence of anorganoaluminum compound was tried in the same way as in ComparativeExample 9 except that 1.15 ml of a cyclohexane solution ofsec-butyllithium (concentration: 1.3 M) was used instead of 0.95 ml ofthe cyclohexane solution of tert-butyllithium (concentration: 1.6 M),and the time for polymerizing methyl methacrylate was extended from 2hours to 6 hours.

[0218] However, it was demonstrated that no methyl methacrylate waspolymerized.

[0219] The used chemical substances, adopted polymerization conditionsand results are shown in Table 3 described below.

COMPARATIVE EXAMPLE 11

[0220] Polymerization of methyl methacrylate in the presence of anorganoaluminum compound was tried in the same way as in ComparativeExample 9 except that 1.0 ml of a cyclohexane solution of n-butyllithium(concentration: 1.5 M) was used instead of 0.95 ml of the cyclohexanesolution of tert-butyllithium (concentration: 1.6 M), and the time forpolymerizing methyl methacrylate was extended from 2 hours to 6 hours.

[0221] However, it was demonstrated that no methyl methacrylate waspolymerized.

[0222] The used chemical substances, adopted polymerization conditionsand results are shown in Table 3 described below. TABLE 3 Polymerizationconditions Polymerization results Initiator compound (solution) Organo-Polymerization Conversion Initiation Compound Solution Added aluminumtemperature time of monomer Polymer efficiency name concentration amountcompound (° C.) (hour) (%) Mn Mw/Mn (%) Example 8 Oligo- 0.1 M  1.5 mliB₂Al(BHT) −30 2 100 11900 1.07 93 butadienyl- lithium Example 9tert-Butyl- 1.6 M 0.95 ml iB₂Al(BHT) −30 2 100 13000 1.11 77 lithiumComparative sec-Butyl- 1.3 M 1.15 ml iB₂Al(BHT) −30 6 Not — — — Example10 lithium polymerized Comparative n-Butyl- 1.5 M  1.0 ml iB₂Al(BHT) −306 Not — — — Example 11 lithium polymerized

[0223] In the above-mentioned Table 3, symbol in the column of“organoaluminum compound” means the following compound. iB₂A(BHT):diisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum

[0224] The following can be understood from results of Example 8 shownin Table 3: in the case that in polymerization of a methacrylic ester,using an anionic polymerization initiator compound, in the presence ofan organoaluminum compound having a chemical structure wherein one ofthree bonds of an aluminum atom is bonded through an oxygen atom to anaromatic ring, an addition reaction product of an organic alkali metalcompound such as a low molecular weight alkyllithium and a conjugateddiene compound is used as the anionic polymerization initiator compound,a high initiation efficiency (block efficiency) can be attained. On theother hand, it can be understood from results of Comparative Examples9-11 described in Table 3 that when a common organoaluminum compoundsuch as a low molecular weight alkyllithium is used as it is as theanionic polymerization initiator compound, the conversion of themethacrylic ester becomes very low or the initiation efficiency becomeslow.

EXAMPLE 9 Synthesis Example of a Butadiene/Methyl Methacrylate DiblockCopolymer

[0225] The present example is a production example of a butadiene/methylmethacrylate diblock copolymer comprising the step of preparing a livinganion of polybutadiene (polybutadienyllithium: a polymerizationinitiator compound) by subjecting butadiene to addition reaction(polymerization) with sec-butyllithium (an organic alkali metalcompound) in a large ratio of the former to the latter, and the step ofpolymerizing methyl methacrylate in the presence ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum (anorganoaluminum compound).

[0226] (1) The inside of a 1 liter autoclave was replaced by nitrogen.Thereto were added 520 g of toluene and 2.5 ml of a cyclohexane solutionof sec-butyllithium (concentration: 1.3 M). To the resultant solutionwas added 65 g of butadiene at 18° C., and then polymerization wasconducted for 5 hours to obtain a living anion of polybutadiene.

[0227] A sample was collected from the resultant reaction mixturesolution, and then GPC measurement thereof proved that the resultantpolybutadiene had a number average molecular weight (Mn), reduced topolystyrene, of 29400 and a molecular weight distribution (Mw/Mn) of1.01.

[0228] (2) The reaction mixture solution obtained in the step (1) wascooled to −3° C., and then thereto was added a mixture solution preparedby mixing 20 ml of a toluene solution ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum (concentration:0.8 M) with 6 ml of 1,2-dimethoxyethane. The resultant solution wasstirred for 10 minutes. Furthermore, thereto was added a mixturesolution prepared by mixing 65 g of methyl methacrylate with 3 ml of atoluene solution ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum (concentration:0.8 M). Polymerization was then conducted at 0° C. for 2 hours.

[0229] A sample was collected from the resultant reaction mixturesolution. GPC measurement thereof proved that the resultant polymer hada number average molecular weight (Mn), reduced to polystyrene, of 49300and a molecular weight distribution (Mw/Mn) of 1.03. No peak originatingfrom polybutadiene (a homopolymer) obtained in the step (1) wasobserved, and it was proved that the resultant polymer was only abutadiene/methyl methacrylate diblock copolymer (PBd-b-PMMA)Furthermore, ¹H-NMR analysis of the sample proved that the weight ratioof the polybutadiene block to the polymethyl methacrylate block in theresultant polymer was 47/53 and the ratio (mole ratio) of the1,4-bonds/the 1,2-bonds in the polybutadiene block was 10/90.

REFERENCE EXAMPLE 1

[0230] The present reference example is a production example of a blockcopolymer wherein a polybutadiene block was substantially changed to anethylene/butylene copolymer block by hydrogenating the block copolymerobtained in Example 9.

[0231] A nickel/aluminum catalyst for hydrogenation (the nickel content:1 mol; the aluminum content: 3 mmol) was added to the reaction mixturesolution which was finally obtained in Example 9. The resultant mixturesolution was stirred under the atmosphere of pressured hydrogen (1 MPa)while the temperature thereof was raised to 80° C. At this temperature,reaction was conducted for 3 hours. During this reaction, the hydrogenpressure was kept at 1 MPa by supplying hydrogen.

[0232]¹H-NMR analysis of the resultant reaction mixture solution provedthat in the produced polymer, 98% of the double bonds of thepolybutadiene block was lost and a diblock copolymer having ahydrogenated polybutadiene block and a poly(methyl methacrylate) block((hydrogenated PBd)-b-PMMA) was obtained.

EXAMPLE 10 Synthesis Example of an Isoprene/N-Butyl Acrylate DiblockCopolymer

[0233] The present example is a production example of isoprene/n-butylacrylate diblock copolymer comprising the step of preparing a livinganion of polyisoprene (polyisoprenyllithium: a polymerization initiatorcompound) by subjecting isoprene to addition reaction (polymerization)with sec-butyllithium (an organic alkali metal compound) in a largeratio of the former to the latter, and the step of polymerizing n-butylacrylate in the presence ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum (anorganoaluminum compound).

[0234] (1) The inside of a 1 liter autoclave was replaced by nitrogen.Thereto were added 440 g of toluene and 2.8 ml of a toluene solution ofsec-butyllithium (concentration: 1.3 M). To the resultant solution wasadded 55 g of isoprene at 23° C., and then polymerization was conductedfor 4 hours to obtain a living anion of polyisoprene.

[0235] A sample was collected from the resultant reaction mixturesolution. GPC measurement thereof proved that the resultant polyisoprenehad a number average molecular weight (Mn), reduced to polystyrene, of11000 and a molecular weight distribution (Mw/Mn) of 1.02.

[0236] (2) The reaction mixture solution obtained in the step (1) wascooled to −31° C., and then thereto was added a mixture solutionprepared by mixing 40 ml of a toluene solution ofisobutylbis(2.6-di-tert-butyl-4-methylphenoxy)aluminum (concentration:0.8 M) with 7 ml of 1,2-dimethoxyethane. The resultant solution wasstirred for 10 minutes. Furthermore, thereto was added a mixturesolution prepared by mixing 55 g of n-butyl acrylate with 5 ml of atoluene solution ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum (concentration:0.8 M), so as to conduct polymerization at −27° C. for 2 hours.

[0237] A sample was collected from the resultant reaction mixturesolution. GPC measurement thereof proved that the resultant polymer hada number average molecular weight (Mn), reduced to polystyrene, of 37800and a molecular weight distribution (Mw/Mn) of 1.03. No peak originatingfrom polyisoprene (a homopolymer) obtained in the step (1) was observed,and it was proved that the resultant polymer was only anisoprene/n-butyl acrylate diblock copolymer (PIp-b-PnBA). Furthermore,¹H-NMR analysis of the sample proved that the weight ratio of thepolyisoprene block to the poly(n-butyl acrylate) block in the resultantpolymer was 49/51 and the ratio (mole ratio) of the 1,4-bonds/the3,4-bonds in the polyisoprene block was 7/93.

[0238] A GPC chart of the resultant isoprene/n-butyl acrylate diblockcopolymer and a GPC chart of polyisoprene prepared in the step (1) areshown together in FIG. 1. In FIG. 1, curves A and B show theisoprene/n-butyl acrylate diblock copolymer and the polyisoprene,respectively.

[0239] Examples 9 and 10 demonstrate that according to the productionprocess of the present invention, a block copolymer having a dienepolymer block and a (meth)acrylic ester polymer block can be producedwith a narrow molecular weight distribution and a very high blockefficiency.

[0240] As is evident from Examples 1-10, according to the polymerizationprocess (X) of the present invention, various (meth)acrylic esters suchas tert-butyl methacrylate, methyl methacrylate or n-butyl acrylate canbe anionically polymerized with a high initiation efficiency and a highliving polymerization property in a solvent, such as a hydrocarbonsolvent, which can easily be recovered and reused under a mild coolingcondition, for example, under a temperature condition of −30 to 15° C.,using an organic alkali metal compound, such as sec-butyllithium, whichhas relatively good convenience. Accordingly, according to thispolymerization process, a (meth)acrylic ester polymer, such as a blockcopolymer or the like, can be produced with industrial profitability.

REFERENCE EXAMPLE 2 Preparation of 1,1-diphenyl-3-methylpentyllithium

[0241] To a 500 ml Schlenk tube, in which a magnetic stirrer chip wasput, was added 2.0 g of 1,1-diphenylethylene and then the inside thereofwas replaced by nitrogen. Thereto were added 190 ml of toluene and 7.7ml of a cyclohexane solution of sec-butyllithium (concentration: 1.3 M).The resultant solution was stirred at room temperature for 2 days toconduct reaction. In this way, a toluene solution of1,1-diphenyl-3-methylpentyllithium (DPMPLi) (concentration: 0.05 M) wasobtained.

EXAMPLE 11 Polymerization Example of Methyl Methacrylate, using1,1-diphenyl-3-methylpentyllithium

[0242] The present example is a polymerization example of methylmethacrylate (MMA) wherein 1,1-diphenyl-3-methylpentyllithium (DPMPLi),which is an addition reaction product of sec-butyllithium (an organicalkali metal compound) and 1,1-diphenylethylene, was used as apolymerization initiator compound to bring a mixture ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum (an organoaluminumcompound) and MMA into contact with the above-mentioned polymerizationinitiator compound.

[0243] (1) At room temperature, 0.29 ml of a toluene solution containing0.20 mmol of diisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum, and2.0 g of MMA were stirred under the atmosphere of nitrogen for 10minutes, to prepare a mixture (a liquid product) of the two.

[0244] (2) A magnetic stirrer chip was put into a 50 ml Schlenk tubewith a three-way cock, and then the inside thereof was replaced bynitrogen. Thereto were added 20 ml of toluene and 4 ml of a toluenesolution of DPMPLi obtained in Reference Example 2 (the DPMPLi content:0.20 mmol). The resultant solution was cooled to −25° C. Next, to thissolution was added the mixture ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum and MMA, which wasobtained in the step (1), so as to conduct polymerization with stirringat −25° C. for 1 hour.

[0245] A sample was collected from the resultant reaction mixturesolution. GC (gas chromatography) analysis thereof proved that theconversion of MMA was 100%.

[0246] GPC (gas permeation chromatography) measurement of the resultantpolymer proved that poly(methyl methacrylate) having a number averagemolecular weight (Mn), reduced to polystyrene, of 15000 and a molecularweight distribution (Mw/Mn) of 1.09 was obtained. This fact demonstratedthat the initiation efficiency thereof was 68%.

COMPARATIVE EXAMPLE 12

[0247] Polymerization was conducted with stirring at −25° C. for 1 hourin the same way as in the step (2) in Example 11 except that instead ofthe addition of the mixture ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum and MMA to thetoluene solution of DPMPLi at −25° C., the procedure of adding 0.20 mmolof diisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum to the samesolution and adding 2.0 g of MMA with which no substance was mixedthereto after 10 minutes was adopted.

[0248] A sample was collected from the resultant reaction mixturesolution. GC analysis thereof proved that the conversion of MMA was 30%.

[0249] GPC measurement of the resultant polymer proved that poly(methylmethacrylate) having a number average molecular weight (Mn), reduced topolystyrene, of 33500 and a molecular weight distribution (Mw/Mn) of1.09 was obtained. This fact demonstrated that the initiation efficiencythereof was 30%.

EXAMPLE 12 Polymerization Example of Methyl Methacrylate, using1,1-diphenyl-3-methylpentyllithium

[0250] (1) In the same way as in the step (1) in Example 11, 0.29 ml ofa toluene solution containing 0.20 mmol ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy) aluminum, and 0.02 g ofMMA were used to prepare a mixture (a liquid product) of the two.

[0251] (2) In the same way as in the step (1) in Example 11, 1.14 ml ofa toluene solution containing 0.80 mmol ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum, and 2.0 g of MMAwere used to prepare a mixture (a liquid product) of the two.

[0252] (3) A magnetic stirrer chip was put into a 50 ml Schlenk tubewith a three-way cock, and then the inside thereof was replaced bynitrogen. Thereto were added 20 ml of toluene and 4 ml of a toluenesolution of DPMPLi obtained in Reference Example 2 (the DPMPLi content:0.20 mmol). The resultant solution was cooled to −25° C. Next, to thissolution was added the mixture ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum and MMA, which wasobtained in the step (1), and the resultant solution was stirred at −25°C. for 5 minutes. To this solution was further added the mixture ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum and MMA, which wasobtained in the step (2). The resultant solution was stirred at −25° C.for 1 hour to conduct polymerization.

[0253] A sample was collected from the resultant reaction mixturesolution. GC analysis thereof proved that the polymerization ratio ofMMA was 100%.

[0254] GPC measurement of the resultant polymer proved that poly(methylmethacrylate) having a number average molecular weight (Mn), reduced topolystyrene, of 11100 and a molecular weight distribution (Mw/Mn) of1.10 was obtained. This fact demonstrated that the initiation efficiencythereof was 91%.

EXAMPLE 13 Synthesis Example of a Styrene/Methyl Methacrylate BlockCopolymer

[0255] The present example is a production example of a styrene/methylmethacrylate block copolymer (PSt-b-PMMA), comprising the step ofpreparing polystyryllithium (an organic alkali metal compound) byanionic polymerization of styrene, the step of preparing apolymerization initiator compound by addition reaction of thepolystyryllithium and 1,1-diphenylethylene, the step of preparing amixture of diisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum (anorganoaluminum compound) and methyl methacrylate (MMA), and the step ofpolymerization of MMA by bringing the mixture into contact withthe-above-mentioned polymerization initiator compound. Using the factthat any styrene polymer has a property of UV absorption but any polymerof methyl methacrylate (PMMA) does not have a property of UV absorption,the block efficiency in the block copolymerization (the initiationefficiency in the polymerization of MMA) was obtained.

[0256] (1) A magnetic stirrer chip was put into a 50 ml Schlenk tubewith a three-way cock, and then the inside thereof was replaced bynitrogen. Thereto were added 25 ml of toluene and 0.12 ml of acyclohexane solution containing 0.15 mmol of sec-butyllithium. To thismixture solution was added 0.75 g of styrene, and then the resultantsolution was stirred at 23° C. for 3 hours to prepare a solutioncontaining polystyryllithium.

[0257] (2) To the solution in the Schlenk tube, which was obtained inthe above-mentioned step (1), was added 0.14 g of 1,1-diphenylethylene.Reaction was conducted for 20 hours while the solution was heated at 40°C. As a result, the color of solution was changed from orange color todark red color. This fact demonstrated that polystyryllithium wasreacted with 1,1-diphenylethylene.

[0258] About 0.5 ml of a sample was collected from the resultantreaction mixture solution, and subjected to GC. As a result, it wasproved that the conversion of styrene was 99% or more (on the basis ofused styrene) and the conversion of 1,1-diphenylethylene was 19% (on thebasis of used 1,1-diphenylethylene). Analysis of GPC proved that thenumber average molecular weight (Mn), reduced to polystyrene, of theresultant addition reaction product of polystyryllithium and1,1-diphenylethylene was 5800 and the ratio of the weight averagemolecular weight to the number average molecular weight (Mw/Mn) was1.02.

[0259] (3) In the same way as in the step (1) in Example 11, 0.19 ml ofa toluene solution containing 0.15 mmol ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum, and 0.02 g of MMAwere used to prepare a mixture (a liquid product) of the two.

[0260] (4) In the same way as in the step (1) in Example 11, 0.80 ml ofa toluene solution containing 0.65 mmol ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum, and 2.23 g of MMAwere used to prepare a mixture (a liquid product) of the two.

[0261] (5) The solution in the Schlenk tube, which was obtained in thestep (2), was cooled to −30° C. Next, to this solution was added themixture of diisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum andMMA, which was obtained in the step (3). The resultant solution wasstirred for 10 minutes. To this solution was added the mixture ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum and MMA, which wasobtained in the step (4). The resultant solution was stirred at the sametemperature for 3 hours to conduct polymerization.

[0262] A part of the resultant reaction mixture solution was sampled,and was then analyzed by GC. As a result, it was proved that theconversion of MMA was 100%.

[0263] GPC-UV (254 nm) measurement of the resultant polymer componentproved that the resultant polymer component was a mixture of a blockcopolymer having a number average molecular weight (Mn), reduced topolystyrene, of 24600 and a polymer having a number average molecularweight (Mn), reduced to polystyrene, of 5600 and originating from thepolymerization initiator compound (polystyrene having a1,1-diphenylethylene fragment at its terminal) and the weight ratio ofthe former to the latter was 90/10. This fact demonstrated that theblock efficiency in the block copolymerization was 90%.

COMPARATIVE EXAMPLE 13 Synthesis Example of a Styrene/MethylMethacrylate Block Copolymer

[0264] The present comparative example is a production example of astyrene/methyl methacrylate block copolymer (PSt-b-PMMA) wherein theconditions in the steps (3)-(5) in Example 13 were changed in such amanner that polymerization was conducted by addingdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum as anorganoaluminum compound, separately from MMA, to the solution containingthe polymerization initiator compound and subsequently adding MMAthereto.

[0265] (1) The same way as in the steps (1) and (2) in Example 13 wasperformed, to prepare a solution of an addition reaction product of thepolystyryllithium and 1,1-diphenylethylene. The conversion of styrenewas 99% or more (on the basis of used styrene). The conversion of1,1-diphenylethylene was 21% (on the basis of used1,1-diphenylethylene). Analysis of GPC proved that the number averagemolecular weight (Mn), reduced to polystyrene, of the resultant additionreaction product was 5600 and the ratio of the weight average molecularweight to the number average molecular weight (Mw/Mn) was 1.03.

[0266] (2) The solution in the Schlenk tube, which was obtained in thestep (1), was cooled to −30° C. To this solution was added 1.0 ml of atoluene solution containing 0.80 mol ofdiisobutyl(2,6-di-tert-butyl-4-methylphenoxy)aluminum. The resultantsolution was stirred for 10 minutes. To this solution was further added2.25 g of MMA. The resultant solution was stirred at the sametemperature for 3 hours to conduct polymerization.

[0267] A part of the resultant reaction mixture solution was sampled,and was then analyzed by GC. As a result, it was proved that theconversion of MMA was 100%.

[0268] GPC-UV (254 nm) measurement of the resultant polymer componentproved that the resultant polymer component was a mixture of a blockcopolymer whose number average molecular weight (Mn), reduced topolystyrene, was 38800 and whose ratio of the weight average molecularweight to the number average molecular weight (Mw/Mn) was 1.07, a dimerof the polymerization initiator compound (a compound presumed as acoupled product obtained by nucleophilically adding two molecules of thepolymerization initiator compound anion to the carbonyl group of onemolecule of MMA) and a polymer originating from the polymerizationinitiator compound (polystyrene having a 1,1-diphenylethylene fragmentat its terminal) and the weight ratio among them was 54/9/33. This factdemonstrated that the block efficiency in the block copolymerization was54%.

EXAMPLE 14 Synthesis Example of a Styrene/Methyl Methacrylate BlockCopolymer

[0269] The present example is a production example of a styrene/methylmethacrylate block copolymer (PSt-b-PMMA), comprising the step ofpreparing polystyryllithium (an organic alkali metal compound) byanionic polymerization of styrene, the step of preparing apolymerization initiator compound by addition reaction of thepolystyryllithium and 1,1-diphenylethylene, the step of preparing amixture of isobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum (anorganoaluminum compound) and methyl methacrylate (MMA), and the step ofpolymerization of MMA by bringing the mixture into contact with theabove-mentioned polymerization initiator compound.

[0270] (1) The same way as in the steps (1) and (2) in Example 13 wasperformed, to prepare a solution containing an addition reaction productof the polystyryllithium and 1,1-diphenylethylene. The conversion ofstyrene was 99% or more (on the basis of used styrene). The conversionof 1,1-diphenylethylene was 21% (on the basis of used1,1-diphenylethylene). Analysis of GPC proved that the number averagemolecular weight (Mn), reduced to polystyrene, of the resultant additionreaction product was 5600 and the ratio of the weight average molecularweight to the number average molecular weight (Mw/Mn) was 1.03.

[0271] (2) In the same way as in the step (1) in Example 11, 1.0 ml of atoluene solution containing 0.80 mmol ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum, 2.5 g of 1,2-dimethoxyethane and 2.25 g of MMA were used to prepare a mixture (aliquid product) of the three.

[0272] (3) The solution in the Schlenk tube, which was obtained in thestep (1), was cooled to 0° C. Next, to this solution was added themixture obtained in the step (2). The resultant solution was stirred for3 hours to conduct polymerization.

[0273] A part of the resultant reaction mixture solution was sampled,and was then analyzed by GC. As a result, it was proved that theconversion of MMA was 100%.

[0274] GPC-UV (254 nm) measurement of the resultant polymer componentproved that this polymer component was a mixture of a block copolymerhaving a number average molecular weight (Mn), reduced to polystyrene,of 23100 and a polymer having a number average molecular weight (Mn),reduced to polystyrene, of 5700 and originating from the polymerizationinitiator compound (polystyrene having a 1,1-diphenylethylene fragmentat its terminal) and the weight ratio between them was 92/8. This factdemonstrated that the block efficiency in the block copolymerization was92%.

EXAMPLE 15 Synthesis Example of a Styrene/N-Butyl Acrylate BlockCopolymer

[0275] The present example is a production example of a styrene/n-butylacrylate block copolymer (PSt-b-PnBA), comprising the step of preparingpolystyryllithium (an organic alkali metal compound) by anionicpolymerization of styrene, the step of preparing a polymerizationinitiator compound by addition reaction of the polystyryllithium and1,1-diphenylethylene, the step of preparing a mixture ofisobutylbis(2.6-di-tert-butyl-4-methylphenoxy)aluminum (anorganoaluminum compound) and n-butyl acrylate (nBA), and the step ofpolymerization of nBA by bringing the mixture into contact with theabove-mentioned polymerization initiator compound.

[0276] (1) The same way as in the steps (1) and (2) in Example 13 wasperformed, to prepare a solution containing an addition reaction productof the polystyryllithium and 1,1-diphenylethylene. The conversion ofstyrene was 99% or more (on the basis of used styrene). The conversionof 1,1-diphenylethylene was 23% (on the basis of used1,1-diphenylethylene). Analysis of GPC proved that the number averagemolecular weight (Mn), reduced to polystyrene, of the resultant additionreaction product was 5700 and the ratio of the weight average molecularweight to the number average molecular weight (Mw/Mn) was 1.03.

[0277] (2) In the same way as in the step (1) in Example 11, 1.0 ml of atoluene solution containing 0.80 mmol ofisobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum, 2.5 g of1,2-dimethoxyethane and 2.25 g of nBA were used to prepare a mixture (aliquid product) of the three.

[0278] (3) The solution in the Schlenk tube, which was obtained in thestep (1), was cooled to −30° C. To this solution was added the mixtureobtained in the step (2). The resultant solution was stirred for 2 hoursto conduct polymerization.

[0279] A part of the resultant reaction mixture solution was sampled,and was then analyzed by GC. As a result, it was proved that theconversion of nBA was 100%.

[0280] GPC-UV (254 nm) measurement of the resultant polymer componentproved that this polymer component was a mixture of a block copolymerhaving a number average molecular weight (Mn), reduced to polystyrene,of 29500 and a polymer having a number average molecular weight (Mn),reduced to polystyrene, of 5600 and originating from the polymerizationinitiator compound (polystyrene having a 1,1-diphenylethylene fragmentat its terminal) and the weight ratio between them was 75/25. This factdemonstrated that the block efficiency in the block copolymerization was75%.

[0281] As is evident from Examples 11-15, according to thepolymerization process (Y) of the present invention, (meth)acrylicesters such as methyl methacrylate or n-butyl acrylate can beanionically polymerized with a high initiation efficiency and a highliving polymerization property in a solvent which can easily berecovered and reused under a mild cooling condition, for example, undera temperature condition of −30 to 0° C., using an organic alkali metalcompound which has relatively good convenience. Accordingly, accordingto this polymerization process, (meth)acrylic esters can be subjected toliving anionic polymerization, using any one of initiators havingvarious structures, so that (meth)acrylic ester polymers, such as ablock copolymer or the like, can be produced with industrialprofitability.

What is claimed is:
 1. A polymerization process for polymerizing amethacrylic ester or an acrylic ester anionically, using apolymerization initiator compound, wherein an addition reaction productof a conjugated diene compound and an organic alkali metal compound isused as the polymerization initiator compound, and a tertiaryorganoaluminum compound having in the molecule thereof a chemicalstructure represented by a formula: Al—O—Ar wherein Ar represents anaromatic ring is caused to be present in the polymerization system. 2.The polymerization process according to claim 1, wherein the methacrylicester or the acrylic ester is an ester of a primary alcohol andmethacrylic acid or acrylic acid.
 3. The polymerization processaccording to claim 1, wherein the conjugated diene compound is1,3-butadiene.
 4. The polymerization process according to claim 1,wherein the organic alkali metal compound is a low molecular weightorganic monolithium compound having a secondary carbon atom or a primarycarbon atom as an anionic center.
 5. The polymerization processaccording to claim 1, wherein the organic alkali metal compound is alithium salt of a polymer having a chemical structure in which a lithiumatom or lithium atoms are bonded to at least one molecular terminal. 6.The polymerization process according to claim 1, wherein the tertiaryorganoaluminum compound has a chemical structure in which two or more ofthree bonds that its aluminum atom has are bonded through an oxygen atomto an aromatic ring.
 7. The polymerization process according to claim 1,wherein at least one part of the tertiary organoaluminum compound ismixed with the methacrylic ester or the acrylic ester and subsequentlythe resultant mixture is added to the polymerization system.
 8. Thepolymerization process according to claim 1, wherein an ether compoundor a tertiary polyamine compound is caused to be present in thepolymerization system.
 9. A process for producing a polymer, comprisingpolymerizing a methacrylic ester or an acrylic ester by thepolymerization process according to claim
 1. 10. A process for producinga block copolymer, comprising polymerizing a methacrylic ester or anacrylic ester by the polymerization process according to claim
 5. 11. Apolymerization process for polymerizing a methacrylic ester or anacrylic ester anionically, using a polymerization initiator compound,wherein an addition reaction product of a compound having a1,1-diaryl-1-alkene structure and an organic alkali metal compound isused as the polymerization initiator compound; and the methacrylic esteror the acrylic ester is mixed with a tertiary organoaluminum compoundhaving in the molecule thereof a chemical structure represented by aformula: Al—O—Ar wherein Ar represents an aromatic ring, and then theresultant mixture is added to the polymerization system.
 12. Thepolymerization process according to claim 11, wherein the methacrylicester or the acrylic ester is an ester of a primary alcohol andmethacrylic acid or acrylic acid.
 13. The polymerization processaccording to claim 11, wherein the compound having the1,1-diaryl-1-alkene structure is 1,1-diphenylethylene.
 14. Thepolymerization process according to claim 11, wherein the organic alkalimetal compound is a low molecular weight organic monolithium compoundhaving a secondary carbon atom or a primary carbon atom as an anioniccenter.
 15. The polymerization process according to claim 11, whereinthe organic alkali metal compound is a lithium salt of a polymer havinga chemical structure in which a lithium atom or lithium atoms are bondedto at least one molecular terminal.
 16. The polymerization processaccording to claim 11, wherein the tertiary organoaluminum compound hasa chemical structure in which two or more of three bonds that itsaluminum atom has are bonded through an oxygen atom to an aromatic ring.17. The polymerization process according to claim 11, wherein an ethercompound or a tertiary polyamine compound is caused to be present in thepolymerization system.
 18. A process for producing a polymer, comprisingpolymerizing a methacrylic ester or an acrylic ester by thepolymerization process according to claim
 11. 19. A process forproducing a block copolymer, comprising polymerizing a methacrylic esteror an acrylic ester by the polymerization process according to claim 15.